Polyethylene Compositions and Articles With Good Barrier Properties

ABSTRACT

A dual reactor solution polymerization process gives polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer and which has a balance of barrier properties, toughness and environmental resistance. The polyethylene compositions are suitable for end use applications which may benefit from low oxygen transmission rates such as closures for bottles or barrier film.

TECHNICAL FIELD

The present invention relates to polyethylene compositions that areuseful in the manufacture of articles in which good barrier propertiesare desirable, such as for example, closures for bottles or barrierfilm.

BACKGROUND ART

Work has been done to develop polyethylene compositions which comprisetwo ethylene homopolymer components where the components chosen are ofrelatively low and relatively high molecular weight. These ethylenehomopolymer compositions, which may have a bimodal molecular weightdistribution profile, have been usefully applied in the formation offilms having good barrier properties (see for example U.S. Pat. Nos.7,737,220 and 9,587,093, and U.S. Pat. Appl. Pub. Nos 2008/0118749,2009/0029182 and 2011/0143155).

Although polyethylene compositions comprising a first and a secondethylene copolymer of differing relative molecular weights and densityhave found application in molding applications such as closures (see forexample U.S. Pat. Nos. 9,758,653; 9,074,082; 9,475,927; 9,783,663;9,783,664; 8,962,755; 9,221,966; 9,371,442 and 8,022,143), less emphasishas so far been placed on the barrier properties of such resins (see forexample WO 2016/135590).

SUMMARY OF INVENTION

We have found that when polyethylene copolymer compositions are suitablydesigned, they can have good barrier properties when made into, forexample, a compression molded film or an injection molded closure.

An embodiment of the disclosure is a polyethylene copolymer compositioncomprising: (1) 10 to 70 wt % of a first ethylene copolymer having amelt index I₂, of from 0.1 to 10 g/10 min; a molecular weightdistribution M_(w)/M_(n), of less than 3.0; and a density of from 0.910to 0.946 g/cm³; and (2) 90 to 30 wt % of a second ethylene copolymerhaving a melt index I₂, of from 25 to 1,500 g/10 min; a molecular weightdistribution M_(w)/M_(n), of less than 3.0; and a density higher thanthe density of the first ethylene copolymer, but less than 0.970 g/cm³;wherein the density of the second ethylene copolymer is less than 0.037g/cm³ higher than the density of the first ethylene copolymer; the ratio(SCB1/SCB2) of the number of short chain branches per thousand carbonatoms in the first ethylene copolymer (SCB1) to the number of shortchain branches per thousand carbon atoms in the second ethylenecopolymer (SCB2) is greater than 1.0; and wherein the polyethylenecopolymer composition has a molecular weight distribution M_(w)/M_(n),of from 1.8 to 7.0; a density of less than 0.949 g/cm³; a high load meltindex I₂₁, of at least 150 g/10 min; a Z-average molecular weight M_(z),of less than 200,000; a melt flow ratio I₂₁/I₂, of from 20 to 50; astress exponent of less than 1.40; and an ESCR Condition B (100% IGEPAL)of at least 3.5 hours; and wherein the polyethylene copolymercomposition further comprises a nucleating agent.

An embodiment of the disclosure is a closure for bottles, the closurecomprising a polyethylene copolymer composition comprising: (1) 10 to 70wt % of a first ethylene copolymer having a melt index I₂, of from 0.1to 10 g/10 min; a molecular weight distribution M_(w)/M_(n), of lessthan 3.0; and a density of from 0.910 to 0.946 g/cm³; and (2) 90 to 30wt % of a second ethylene copolymer having a melt index I₂, of from 25to 1,500 g/10 min; a molecular weight distribution M_(w)/M_(n), of lessthan 3.0; and a density higher than the density of the first ethylenecopolymer, but less than 0.970 g/cm³; wherein the density of the secondethylene copolymer is less than 0.037 g/cm³ higher than the density ofthe first ethylene copolymer; the ratio (SCB1/SCB2) of the number ofshort chain branches per thousand carbon atoms in the first ethylenecopolymer (SCB1) to the number of short chain branches per thousandcarbon atoms in the second ethylene copolymer (SCB2) is greater than1.0; and wherein the polyethylene copolymer composition has a molecularweight distribution M_(w)/M_(n), of from 1.8 to 7.0; a density of lessthan 0.949 g/cm³; a high load melt index I₂₁, of at least 150 g/10 min;a Z-average molecular weight M_(z), of less than 200,000; a melt flowratio I₂₁/I₂, of from 20 to 50; a stress exponent of less than 1.40; andan ESCR Condition B (100% IGEPAL) of at least 3.5 hours; and wherein thepolyethylene copolymer composition further comprises a nucleating agent.

An embodiment of the disclosure is a film, the film comprising apolyethylene copolymer composition comprising: (1) 10 to 70 wt % of afirst ethylene copolymer having a melt index I₂, of from 0.1 to 10 g/10min; a molecular weight distribution M_(w)/M_(n), of less than 3.0; anda density of from 0.910 to 0.946 g/cm³; and (2) 90 to 30 wt % of asecond ethylene copolymer having a melt index I₂, of from 25 to 1,500g/10 min; a molecular weight distribution M_(w)/M_(n), of less than 3.0;and a density higher than the density of the first ethylene copolymer,but less than 0.970 g/cm³; wherein the density of the second ethylenecopolymer is less than 0.037 g/cm³ higher than the density of the firstethylene copolymer; the ratio (SCB1/SCB2) of the number of short chainbranches per thousand carbon atoms in the first ethylene copolymer(SCB1) to the number of short chain branches per thousand carbon atomsin the second ethylene copolymer (SCB2) is greater than 1.0; and whereinthe polyethylene copolymer composition has a molecular weightdistribution M_(w)/M_(n), of from 1.8 to 7.0; a density of less than0.949 g/cm³; a high load melt index I₂₁, of at least 150 g/10 min; aZ-average molecular weight M_(z), of less than 200,000; a melt flowratio I₂₁/I₂, of from 20 to 50; a stress exponent of less than 1.40; andan ESCR Condition B (100% IGEPAL) of at least 3.5 hours; and wherein thepolyethylene copolymer composition further comprises a nucleating agent.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the gel permeation chromatographs (GPC) of polyethylenecompositions (Examples 1 and 2) made according to the present disclosureusing differential refractometer as the detector.

FIG. 2 shows the normalized oxygen transmission rates (OTR) ofcompression molded films made from nucleated polyethylene compositions(Examples 1* and 2*) according to the present disclosure vs. the densityof the nucleated polyethylene compositions (Examples 1* and 2*). FIG. 2also shows the normalized oxygen transmission rates (OTR) of compressionmolded films made from comparative nucleated polyethylene compositions(Examples 3*, 4* and 5*) vs. the density of the comparative nucleatedpolyethylene compositions (Examples 3*, 4* and 5*).

FIG. 3 shows the normalized water vapor transmission rates (WVTR) ofcompression molded films made from nucleated polyethylene compositions(Examples 1* and 2*) according to the present disclosure vs. the densityof the nucleated polyethylene compositions (Examples 1* and 2*). FIG. 3also shows the normalized water vapor transmission rates (WVTR) ofcompression molded films made from comparative nucleated polyethylenecompositions (Examples 3*, 4* and 5*) vs. the density of the comparativenucleated polyethylene compositions (Examples 3*, 4* and 5*).

FIG. 4 shows the oxygen transmission rates (OTR) of injection moldedclosures made from nucleated polyethylene compositions (Examples 1* and2*) according to the present disclosure vs. the density of the nucleatedpolyethylene compositions (Examples 1* and 2*). FIG. 4 also shows theoxygen transmission rates (OTR) of injection molded closures made fromcomparative nucleated polyethylene compositions (Examples 3*, 4* and 5*)vs. the density of the comparative nucleated polyethylene compositions(Examples 3*, 4* and 5*).

FIG. 5 shows the ESCR (condition B, at 100% IGEPAL) for polyethylenecompositions (Examples 1 and 2) made according to the present disclosurevs. the oxygen transmission rate (OTR) of injection molded closures madefrom nucleated polyethylene compositions made according to the presentdisclosure (Examples 1* and 2*). FIG. 5 also shows the ESCR (conditionB, at 100% IGEPAL) for comparative polyethylene compositions (Examples3, 4 and 5) vs. the oxygen transmission rate (OTR) of injection moldedclosures made from comparative nucleated polyethylene compositions(Examples 3*, 4* and 5*).

FIG. 6 shows the notched Izod impact strength for nucleated polyethylenecompositions (Examples 1* and 2*) made according to the presentdisclosure vs. the oxygen transmission rate (OTR) of injection moldedclosures made from the nucleated polyethylene compositions madeaccording to the present disclosure (Examples 1* and 2*). FIG. 6 alsoshows the notched Izod impact strength for comparative nucleatedpolyethylene compositions (Examples 3*, 4* and 5*) vs. the oxygentransmission rate (OTR) of injection molded closures made from thecomparative nucleated polyethylene compositions (Examples 3*, 4* and5*).

DESCRIPTION OF EMBODIMENTS

By the terms “ethylene homopolymer” or “polyethylene homopolymer”, or“ethylene homopolymer composition” it is meant that the polymer referredto is the product of a polymerization process, where only ethylene wasdeliberately added as a polymerizable olefin. In contrast, the terms“ethylene copolymer” or “polyethylene copolymer”, or “polyethylenecopolymer composition” mean that the polymer referred to is the productof a polymerization process, where ethylene and one or more than onealpha olefin comonomer were deliberately added as polymerizable olefins.

The term “unimodal” is herein defined to mean there will be only onesignificant peak or maximum evident in a GPC-curve. A unimodal profileincludes a broad unimodal profile. Alternatively, the term “unimodal”connotes the presence of a single maxima in a molecular weightdistribution curve generated according to the method of ASTM D6474-99.In contrast, by the term “bimodal” it is meant that there will be asecondary peak or shoulder evident in a GPC-curve which represents ahigher or lower molecular weight component (i.e. the molecular weightdistribution, can be said to have two maxima in a molecular weightdistribution curve). Alternatively, the term “bimodal” connotes thepresence of two maxima in a molecular weight distribution curvegenerated according to the method of ASTM D6474-99. The term“multi-modal” denotes the presence of two or more maxima in a molecularweight distribution curve generated according to the method of ASTMD6474-99.

In an embodiment of the disclosure a polymer composition comprises from1 to 100 percent by weight of a polyethylene copolymer composition asdefined herein.

In an embodiment of the disclosure, a polyethylene copolymer compositioncomprises two components, (1) a first ethylene copolymer and (2) asecond ethylene copolymer which is different from the first ethylenecopolymer.

In an embodiment of the disclosure, a polyethylene copolymer compositioncomprising two components, (1) a first ethylene copolymer and (2) asecond ethylene copolymer which is different from the first ethylenecopolymer, further comprises a nucleating agent.

The first and second ethylene copolymers as well as the nucleating agentare defined further below.

The First Ethylene Copolymer

In an embodiment of the disclosure the first ethylene copolymercomprises both polymerized ethylene and at least one polymerizedalpha-olefin comonomer, with polymerized ethylene being the majorityspecies.

In an embodiment of the disclosure the first ethylene copolymer is madeusing a single site polymerization catalyst.

In an embodiment of the disclosure the first ethylene copolymer is madeusing a single site polymerization catalyst in a solution phasepolymerization process.

In an embodiment of the disclosure, the comonomer (i.e., alpha-olefin)content in the first ethylene copolymer can be from about 0.05 to about3.0 mol % as measured by ¹³C NMR, or FTIR or GPC-FTIR methods, or ascalculated from a reactor model (see the Examples section). Thecomonomer is one or more suitable alpha olefin, which include, but arenot limited to, 1-butene, 1-hexene, 1-octene and the like. In oneembodiment the alpha olefin is 1-octene.

In an embodiment of the disclosure, the short chain branching in thefirst ethylene copolymer can be from about 0.10 to about 15 short chainbranches per thousand carbon atoms (SCB1/1000 Cs). In furtherembodiments of the disclosure, the short chain branching in the firstethylene copolymer can be from 0.10 to 10, or from 0.20 to 10, or from0.20 to 5, or from 0.20 to 3.5, or from 0.10 to 5, or from 0.10 to 3.5,or from 0.20 to 3.5, or from 0.5 to 5, or from 0.5 to 3.5, or from 1 to10, or from 1 to 5, or from 1 to 3.5 branches per thousand carbon atoms(SCB1/1000 Cs). The short chain branching is the branching due to thepresence of alpha-olefin comonomer in the ethylene copolymer and willfor example have two carbon atoms for a 1-butene comonomer, or fourcarbon atoms for a 1-hexene comonomer, or six carbon atoms for a1-octene comonomer, etc. The comonomer is one or more suitablealpha-olefin, which include, but are not limited to, 1-butene, 1-hexene,1-octene and the like. In one embodiment the alpha olefin is 1-octene.

In embodiments of the disclosure, the comonomer in the first ethylenecopolymer is one or more olefin such as but not limited to 1-butene,1-hexene, 1-octene and the like.

In an embodiment of the disclosure, the first ethylene copolymer is acopolymer of ethylene and 1-octene.

In an embodiment of the disclosure, the comonomer content in the firstethylene copolymer is greater than comonomer content of the secondethylene copolymer (as reported, for example, in mol %).

In an embodiment of the disclosure, the amount of short chain branchingin the first ethylene copolymer is greater than the amount of shortchain branching in the second ethylene copolymer (as reported in shortchain branches, SCB per thousand carbons in the polymer backbone, 1000Cs).

In an embodiment of the disclosure, the melt index, I₂ ¹ of the firstethylene copolymer is less than the melt index, I₂ ² of second ethylenecopolymer.

In embodiments of the disclosure the first ethylene copolymer has a meltindex, I₂ ¹ of ≤10.0 g/10 min, or ≤5.0 g/10 min, or ≤2.5 g/10 min, or≤1.0 g/10 min. In another embodiment of the disclosure, the firstethylene copolymer has a melt index, I₂ ¹ of from 0.001 to 10.0 g/10min, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the melt index, I₂ ¹ of the first ethylene copolymer may befrom 0.001 to 7.5 g/10 min, or from 0.001 to 5.0 g/10 min, or from 0.001to 2.5 g/10 min, or 0.001 to 1.0 g/10 min, or from 0.01 to 10.0 g/10min, or from 0.01 to 7.5 g/10 min, or from 0.01 to 5.0 g/10 min, or from0.01 to 2.5 g/10 min, or from 0.01 to 1.0 g/10 min, or from 0.1 to 10.0g/10 min, or from 0.1 to 7.5 g/10 min, or from 0.1 to 5.0 g/10 min, orfrom 0.1 to 2.5 g/10 min, or from 0.1 to 1.0 g/10 min.

In an embodiment of the disclosure, the first ethylene copolymer has amelt flow ratio, I₂₁/I₂ of less than 25, or less than 23, or less than20.

In an embodiment of the disclosure, the first ethylene copolymer has aweight average molecular weight, M_(w) of from 40,000 to 250,000 g/mol,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the first ethylene copolymer has a weight average molecularweight, M_(w) of from 50,000 to 200,000 g/mol, or from 50,000 to 175,000g/mol, or from 50,000 to 150,000 g/mol, or from 40,000 to 125,000 g/mol,or from 50,000 to 135,000 g/mol.

In embodiments of the disclosure, the first ethylene copolymer has amolecular weight distribution, M_(w)/M_(n) of ≤3.0, or <3.0, or ≤2.7, or<2.7, or ≤2.5, or <2.5, or ≤2.3, or <2.3, or ≤2.1, or <2.1, or about 2.In another embodiment of the disclosure, the first ethylene copolymerhas a molecular weight distribution, M_(w)/M_(n) of from 1.7 to 3.0,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the first ethylene copolymer has a molecular weightdistribution, M_(w)/M_(n) of from 1.8 to 2.7, or from 1.8 to 2.5, orfrom 1.8 to 2.3, or from 1.9 to 2.1.

In an embodiment of the disclosure, the density, d¹ of the firstcopolymer is less than the density, d² of the second ethylene copolymer.

In an embodiment of the disclosure, the first ethylene copolymer has adensity, d¹ of from 0.900 to 0.950 g/cm³, including any narrower rangeswithin this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the first ethylene copolymerhas a density, d¹ of from 0.900 to 0.948 g/cm³, or from 0.905 to 0.948g/cm³, or from 0.910 to 0.948 g/cm³, or from 0.914 to 0.948 g/cm³, orfrom 0.916 to 0.948 g/cm³, or from 0.918 to 0.948 g/cm³, or from 0.920to 0.948 g/cm³, or from 0.922 to 0.948 g/cm³, or from 0.924 to 0.948g/cm³, or from 0.900 to 0.946 g/cm³, or from 0.905 to 0.946 g/cm³, orfrom 0.910 to 0.946 g/cm³, or from 0.912 to 0.946 g/cm³, or from 0.914to 0.946 g/cm³, or from 0.916 to 0.946 g/cm³, or from 0.918 to 0.946g/cm³, or from 0.920 to 0.946 g/cm³, or from 0.922 to 0.946 g/cm³, orfrom 0.924 to 0.946 g/cm³, or from 0.900 to 0.944 g/cm³, or from 0.905to 0.944 g/cm³, or from 0.910 to 0.944 g/cm³, or from 0.914 to 0.944g/cm³, or from 0.916 to 0.944 g/cm³, or 0.918 to 0.942 g/cm³, or from0.920 to 0.942 g/cm³, or from 0.922 to 0.942 g/cm³, or from 0.924 to0.942 g/cm³, or from 0.914 to 0.940 g/cm³, or from 0.916 to 0.940 g/cm³,or 0.918 to 0.940 g/cm³, or from 0.920 to 0.940 g/cm³, or from 0.922 to0.940 g/cm³, or from 0.924 to 0.940 g/cm³, or from 0.914 to 0.938 g/cm³,or from 0.916 to 0.938 g/cm³, or 0.918 to 0.938 g/cm³, or from 0.920 to0.938 g/cm³, or from 0.922 to 0.938 g/cm³, or from 0.924 to 0.938 g/cm³.

In an embodiment of the disclosure, a single site catalyst which givesan ethylene copolymer having a CDBI(50) of at least 65% by weight, or atleast 70%, or at least 75%, or at least 80%, or at least 85%, duringsolution phase polymerization in a single reactor, is used in thepreparation of the first ethylene copolymer.

In an embodiment of the present disclosure, the first ethylene copolymeris ethylene copolymer which has a CDBI(50) of greater than about 60% byweight, or greater than about 65%, or greater than about 70%, or greaterthan about 75%, or greater than about 80%, or greater than about 85%.

In embodiments of the disclosure, the weight percent (wt %) of the firstethylene copolymer in the polyethylene copolymer composition (i.e. theweight percent of the first ethylene copolymer based on the total weightof the first and second ethylene copolymers) may be from about 5 wt % toabout 95 wt %, including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, the weight percent (wt %) of the first ethylene copolymer inthe polyethylene copolymer composition may be from about 5 wt % to about90 wt %, or from about 10 wt % to about 90 wt %, or from about 5 wt % toabout 80 wt %, or from about 10 wt % to about 70 wt %, or from about 5wt % to about 70 wt %, or from about 5 wt % to about 60 wt %, or fromabout 10 wt % to about 50 wt %, or from about 15 wt % to about 45 wt %,or from about 20 wt % to about 40 wt %, or from about 20 wt % to about50 wt %, or from about 20 wt % to about 55 wt %, or from about 20 wt %to about 60 wt %, or from about 25 wt % to about 65 wt %, or from about25 wt % to about 60 wt %, or from about 30 wt % to about 60 wt %, orfrom about 30 wt % to about 55 wt %, or from about 30 wt % to about 50wt %, or from about 30 wt % to about 45 wt %.

The Second Ethylene Copolymer

In an embodiment of the disclosure the second ethylene copolymercomprises both polymerized ethylene and at least one polymerizedalpha-olefin comonomer, with polymerized ethylene being the majorityspecies.

In an embodiment of the disclosure the second ethylene copolymer is madeusing a single site polymerization catalyst.

In an embodiment of the disclosure the second ethylene copolymer is madeusing a single site polymerization catalyst in a solution phasepolymerization process.

In an embodiment of the disclosure, the comonomer content in the secondethylene copolymer can be from about 0.05 to about 3 mol % as measuredby ¹³C NMR, or FTIR or GPC-FTIR methods, or as calculated from a reactormodel (see Examples section). The comonomer is one or more suitablealpha olefins, which include, but are not limited to, 1-butene,1-hexene, 1-octene and the like. In one embodiment the alpha olefin is1-octene.

In an embodiment of the disclosure, the short chain branching in thesecond ethylene copolymer can be from about 0.10 to about 10 short chainbranches per thousand carbon atoms (SCB1/1000 Cs). In furtherembodiments of the disclosure, the short chain branching in the secondethylene copolymer can be from 0.10 to 7.5, or from 0.10 to 5, or from0.10 to 3, or from 0.10 to 1.5 branches per thousand carbon atoms(SCB1/1000 Cs). The short chain branching is the branching due to thepresence of alpha-olefin comonomer in the ethylene copolymer and willfor example have two carbon atoms for a 1-butene comonomer, or fourcarbon atoms for a 1-hexene comonomer, or six carbon atoms for a1-octene comonomer, etc. The comonomer is one or more suitable alphaolefin. Examples of alpha olefins include, but are not limited to1-butene, 1-hexene, 1-octene and the like. In one embodiment the alphaolefin is 1-octene.

In embodiments of the disclosure, the comonomer in the second ethylenecopolymer is one or more olefin such as but not limited to 1-butene,1-hexene, 1-octene and the like.

In an embodiment of the disclosure, the second ethylene copolymer is acopolymer of ethylene and 1-octene.

In an embodiment of the disclosure, the comonomer content in the secondethylene copolymer is less than the comonomer content of the firstethylene copolymer (as reported for example in mol %).

In an embodiment of the disclosure, the amount of short chain branchingin the second ethylene copolymer is less than the amount of short chainbranching in the first ethylene copolymer (as reported in short chainbranches, SCB per thousand carbons in the polymer backbone, 1000 Cs).

In an embodiment of the disclosure, the melt index, I₂ ² of the secondethylene copolymer is greater than the melt index, I₂ ¹ of firstethylene copolymer. In an embodiment of the disclosure, the ratio of themelt index, I₂ ² of the second ethylene copolymer to the melt index, I₂¹ of the first ethylene copolymer is from 1.1 to 1000, including anynarrower ranges within this range and any values encompassed by theseranges. For example, in embodiments of the disclosure, the ratio of themelt index, I₂ ² of the second ethylene copolymer to the melt index, I₂¹ of the first ethylene copolymer may be from 1.1 to 750, or from 1.1 to500.

In embodiments of the disclosure the second ethylene copolymer has amelt index, I₂ ² of from 10 to 5,000 including any narrower rangeswithin this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the melt index, I₂ ² of thesecond ethylene copolymer is from 10 to 2,500 g/10 min, or from 15 to2,500 g/10 min, or from 25 to 5,000 g/10 min, or from 10 to 1,500 g/10min, or from 15 to 1,500 g/10 min, or from 25 to 1,500 g/10 min, or from10 to 1,000 g/10 min, or from 15 to 1,000 g/10 min, or from 25 to 1,000g/10 min, or from 50 to 5,000 g/10 min, or from 50 to 2,500 g/10 min, orfrom 50 to 1,500 g/10 min, or from 50 to 1,000 g/10 min, or from 50, to500 g/10 min, or from 10 to 500 g/10 min, or 15 to 500 g/10 min, or from25 to 500 g/10 min, or from 10 to 250 g/10 min, or from 25 to 250 g/10min, or from 50 to 250 g/10 min.

In an embodiment of the disclosure, the second ethylene copolymer has amelt flow ratio, I₂₁/I₂ of less than 25, or less than 23, or less than20.

In an embodiment of the disclosure, the second ethylene copolymer has aweight average molecular weight, M_(w) of ≤75,000 g/mol, or ≤60,000g/mol, or ≤50,000 g/mol, or ≤45,000 g/mol, or ≤40,000 g/mol, or ≤35,000g/mol, or ≤30,000 g/mol. In another embodiment the second ethylenecopolymer has a weight average molecular weight, M_(w) of from 5,000 to100,000 g/mol, including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, the second ethylene copolymer has a weight average molecularweight, M_(w) of from 10,000 to 75,000 g/mol, or from 15,000 to 65,000g/mol, or from 20,000 to 60,000 g/mol, or from 20,000 to 55,000 g/mol,or from 20,000 to 50,000 g/mol, or from 20,000 to 40,000 g/mol.

In embodiments of the disclosure, the second ethylene copolymer has amolecular weight distribution, M_(w)/M_(n) of ≤3.0, or <3.0, or ≤2.7, or<2.7, or ≤2.5, or <2.5, or ≤2.3, or <2.3, or ≤2.1, or <2.1, or about 2.In another embodiment of the disclosure, the second ethylene copolymerhas a molecular weight distribution, M_(w)/M_(n) of from 1.7 to 3.0,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the second ethylene copolymer has a molecular weightdistribution, M_(w)/M_(n) of from 1.8 to 2.7, or from 1.8 to 2.5, orfrom 1.8 to 2.3, or from 1.9 to 2.1.

In an embodiment of the disclosure, the density, d² of the secondcopolymer is greater than the density, d¹ of the first ethylenecopolymer.

In an embodiment of the disclosure, the density, d² of the secondethylene copolymer is less than 0.037 g/cm³ greater than the density, d¹of the first ethylene copolymer. In an embodiment of the disclosure, thedensity, d² of the second ethylene copolymer is less than 0.035 g/cm³greater than the density, d¹ of the first ethylene copolymer. In anembodiment of the disclosure, the density, d² of the second ethylenecopolymer is less than 0.031 g/cm³ greater than the density, d¹ of thefirst ethylene copolymer. In an embodiment of the disclosure, thedensity, d² of the second ethylene copolymer is less than 0.030 g/cm³greater than the density, d¹ of the first ethylene copolymer. In anembodiment of the disclosure, the density, d² of the second ethylenecopolymer is less than 0.025 g/cm³ greater than the density, d¹ of thefirst ethylene copolymer.

In an embodiment of the disclosure, the second ethylene copolymer has adensity, d² of less than 0.970 g/cm³, or less than 0.967 g/cm³, or lessthan 0.965 g/cm³, or less than 0.963 g/cm³, or less than 0.961 g/cm³.

In an embodiment of the disclosure, the second ethylene copolymer has adensity, d² of from 0.943 to 0.985 g/cm³, including any narrower rangeswithin this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the second ethylene copolymerhas a density, d² of from 0.945 to 0.985 g/cm³, or from 0.947 to 0.985g/cm³, or from 0.950 to 0.985 g/cm³, or from 0.943 to 0.980 g/cm³, orfrom 0.945 to 0.980 g/cm³, or from 0.947 to 0.980 g/cm³, or from 0.950to 0.980 g/cm³, or from 0.951 to 0.985 g/cm³, or from 0.951 to 0.985g/cm³, or from 0.951 to 0.980 g/cm³, or from 0.943 to 0.975 g/cm³, orfrom 0.945 to 0.975 g/cm³, or from 0.947 to 0.975 g/cm³, or from 0.950to 0.975 g/cm³, or from 0.950 to 0.970 g/cm³, or from 0.945 to 0.965g/cm³, or from 0.947 to 0.965 g/cm³, or from 0.946 to 0.963 g/cm³, orfrom 0.948 to 0.963 g/cm³.

In an embodiment of the disclosure, a single site catalyst which givesan ethylene copolymer having a CDBI(50) of at least 65% by weight, or atleast 70%, or at least 75%, or at least 80%, or at least 85%, duringsolution phase polymerization in a single reactor, is used in thepreparation of the second ethylene copolymer.

In an embodiment of the present disclosure, the second ethylenecopolymer is ethylene copolymer which has a CDBI(50) of greater thanabout 60% by weight, or greater than about 65%, or greater than about70%, or greater than about 75%, or greater than about 80%, or greaterthan about 85%.

In embodiments of the disclosure, the weight percent (wt %) of thesecond ethylene copolymer in the polyethylene copolymer composition(i.e. the weight percent of the second ethylene copolymer based on thetotal weight of the first and second ethylene copolymers) may be fromabout 95 wt % to about 5 wt %, including any narrower ranges within thisrange and any values encompassed by these ranges. For example, inembodiments of the disclosure, the weight percent (wt %) of the secondethylene copolymer in the polyethylene copolymer composition may be fromabout 90 wt % to about 10 wt %, or from about 90 wt % to about 20 wt %,or from about 90 wt % to about 30 wt %, or from about 90 wt % to about40 wt %, or from about 90 wt % to about 50 wt %, or from about 80 wt %to about 50 wt %, or from about 80 wt % to about 45 wt %, or from about80 wt % to about 60 wt %, or from about 70 wt % to about 45 wt %, orfrom about 75 wt % to about 50 wt %, or from about 70 wt % to about 55wt %.

The Polyethylene Copolymer Composition

In an embodiment of the disclosure, the polyethylene copolymercomposition will comprise a first ethylene copolymer and a secondethylene copolymer (each as defined herein).

In an embodiment of the disclosure, the polyethylene copolymercomposition has a bimodal profile (i.e. a bimodal molecular weightdistribution) in a gel permeation chromatography (GPC) analysis.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a unimodal profile (i.e. a unimodal molecular weightdistribution) in a gel permeation chromatography (GPC) analysis.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a bimodal profile in a gel permeation chromatographgenerated according to the method of ASTM D6474-99.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a unimodal profile in a gel permeation chromatographgenerated according to the method of ASTM D6474-99.

In an embodiment of the disclosure, the polyethylene copolymercomposition that comprises a first ethylene copolymer and a secondethylene copolymer (as defined above) will have a ratio (SCB1/SCB2) ofthe number of short chain branches per thousand carbon atoms in thefirst ethylene copolymer (i.e., SCB1) to the number of short chainbranches per thousand carbon atoms in the second ethylene copolymer(i.e., SCB2) of greater than 1.0 (i.e., SCB1/SCB2>1.0). In furtherembodiments of the disclosure, the ratio of the short chain branching inthe first ethylene copolymer (SCB1) to the short chain branching in thesecond ethylene copolymer (SCB2) is at least 1.5 or greater than 1.5. Instill further embodiments of the disclosure, the ratio of the shortchain branching in the first ethylene copolymer (SCB1) to the shortchain branching in the second ethylene copolymer (SCB2) is at least 2.0or greater than 2.0. In still another embodiment of the disclosure, theratio of the short chain branching in the first ethylene copolymer(SCB1) to the short chain branching in the second ethylene copolymer(SCB2) is at least 2.5. In embodiments of the disclosure, the ratio(SCB1/SCB2) of the short chain branching in the first ethylene copolymer(SCB1) to the short chain branching in the second ethylene copolymer(SCB2) will be from greater than 1.0 to about 12.0, or from greater than1.0 to about 10, or from greater than 1.0 to about 7.0, or from greaterthan 1.0 to about 5.0, or from about 1.5 to about 10, or from about 1.5to about 7.0, or from about 1.5 to about 5.0.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a weight average molecular weight, M_(w) of ≤100,000g/mol, or ≤75,000 g/mol, or <70,000 g/mol, or ≤65,000 g/mol, or <65,000g/mol or ≤60,000 g/mol, or <60,000 g/mol. In another embodiment, thepolyethylene copolymer composition has a weight average molecularweight, M_(w) of from 20,000 to 125,000 g/mol, including any narrowerranges within this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the polyethylene copolymercomposition has a weight average molecular weight, M_(w) of from 25,000to 100,000 g/mol, or from 25,000 to 90,000 g/mol, or from 30,000 to80,000 g/mol, or from 30,000 to 75,000 g/mol.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a number average molecular weight, M_(n) of ≤60,000g/mol, or ≤50,000 g/mol, or <50,000 g/mol, or ≤45,000 g/mol, or <45,000g/mol, or ≤40,000 g/mol, or <40,000 g/mol, or ≤35,000 g/mol, or <35,000g/mol, or ≤30,000 g/mol, or <30,000 g/mol. In another embodiment of thedisclosure, the polyethylene copolymer composition has a number averagemolecular weight, M_(n) of from 5,000 to 60,000 g/mol, including anynarrower ranges within this range and any values encompassed by theseranges. For example, in embodiments of the disclosure, the polyethylenecopolymer composition has a number average molecular weight, M_(n) offrom 10,000 to 55,000 g/mol, or from 10,000 to 50,000 g/mol, or from15,000 to 50,000 g/mol, or from 15,000 to 45,000 g/mol, or from 15,000to 40,000 g/mol, or from 15,000 to 35,000 g/mol, or from 15,000 to30,000 g/mol, or from 15,000 to 25,000 g/mol.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a Z-average molecular weight, Mz, of below about 200,000g/mol. In another embodiment of the disclosure, the polyethylenecopolymer composition has a Z-average molecular weight, M_(z), of belowabout 175,000 g/mol. In another embodiment of the disclosure, thepolyethylene copolymer composition has a Z-average molecular weight,M_(z), of below about 150,000 g/mol. In yet another embodiment of thedisclosure, the polyethylene copolymer composition has a Z-averagemolecular weight, M_(z), of below about 125,000 g/mol.

In embodiments of the disclosure, the polyethylene copolymer compositionhas a molecular weight distribution, M_(w)/M_(n) of ≤7.0, or <7.0, or≤6.5, or <6.5, or ≤6.0, or <6.0, or 5.5, or <5.5, or ≤5.0, or <5.0, or≤4.5, or <4.5, or ≤4.0, or <4.0, or ≤3.5, or <3.5, or ≤3.0, or <3.0. Inanother embodiment of the disclosure, the polyethylene copolymercomposition has a molecular weight distribution, M_(w)/M_(n) of from 1.7to 7.0, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the polyethylene copolymer composition has a molecularweight distribution, M_(w)/M_(n) of from 1.8 to 7.0, or from 1.8 to 6.5,or from 1.8 to 6.0, or from 1.8 to 5.5, or from 1.8 to 5.0, or from 1.8to 4.5, or from 1.8 to 4.0, or from 1.8 to 3.5, or from 1.8 to 3.0, orfrom 1.8 to 2.5, or from 2.0 to 5.0, or from 2.0 to 4.5, or from 2.0 to4.0, or from 2.0 to 3.5, or from 2.0 to 3.0.

In embodiments of the disclosure, the polyethylene copolymer compositionhas a density of ≤0.950 g/cm³, or <0.950 g/cm³, or ≤0.949 g/cm³, or<0.949 g/cm³, or ≤0.948 g/cm³, or <0.948 g/cm³.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a density of from 0.932 to 0.950 g/cm³, including anynarrower ranges within this range and any values encompassed by theseranges. For example, in embodiments of the disclosure, the polyethylenecopolymer composition has a density of from 0.934 to 0.950 g/cm³, orfrom 0.934 to 0.949 g/cm³, or from 0.934 to less than 0.949 g/cm³, orfrom 0.934 to 0.948 g/cm³, or from 0.936 to 0.950 g/cm³, or from 0.936to 0.949 g/cm³, or from 0.936 to less than 0.949 g/cm³, or from 0.936 to0.948 g/cm³, or from 0.938 to 0.950 g/cm³, or from 0.938 to 0.949 g/cm³,or from 0.938 to less than 0.949 g/cm³, or from 0.938 to 0.948 g/cm³, orfrom 0.939 to 0.950 g/cm³, or from 0.939 to 0.949 g/cm³, or from 0.939to less than 0.949 g/cm³, or from 0.939 to 0.948 g/cm³, or from 0.940 to0.950 g/cm³, or from 0.940 to 0.949 g/cm³, or from 0.940 to less than0.949 g/cm³, or from 0.940 to 0.948 g/cm³, or from 0.941 to 0.950 g/cm³,or from 0.941 to 0.949 g/cm³, or from 0.941 to less than 0.949 g/cm³, orfrom 0.941 to 0.948 g/cm³.

In embodiments of the disclosure the polyethylene copolymer compositionhas a melt index, I₂ of at least 1.0 g/10 min (≥1.0 g/10 min), or atleast 3.0 g/10 min (≥3.0 g/10 min), or at least 5.0 g/10 min (≥5.0 g/10min), or at least 7.5 g/10 min (≥7.5 g/10 min), or at least 10 g/10 min(≥10.0 g/10 min), or greater than 3.0 g/10 min (>3.0 g/10 min), orgreater than 5.0 g/10 min (>5.0 g/10 min), or greater than 7.5 g/10 min(>7.5 g/10 min), or greater than 10.0 g/10 min (>10.0 g/10 min). Inanother embodiment of the disclosure, the polyethylene copolymercomposition has a melt index, I₂ of from 1.0 to 100 g/10 min, includingany narrower ranges within this range and any values encompassed bythese ranges. For example, in embodiments of the disclosure, the meltindex, I₂ of the polyethylene copolymer composition may be from 1.0 to75 g/10 min, or from 1.0 to 50 g/10 min, or from 1 to 25 g/10 min, orfrom 3.0 to 100 g/10 min, or from 3.0 to 75 g/10 min, or from 3.0 to 50g/10 min, or from 3.0 to 25 g/10 min, or from 3.0 to 20.0 g/10 min, orfrom greater than 3.0 to less than 20.0 g/10, or from 5.0 to 100 g/10min, or from 5.0 to 75 g/10 min, or from 5.0 to 50 g/10 min, or from 5.0to 25 g/10 min, or from 5.0 to 20.0 g/10 min, or from greater than 5.0to less than 20.0 g/10 min, or from greater than 10.0 to less than 25.0g/10 min, or from greater than 10.0 to less than 20.0 g/10 min.

In embodiments of the disclosure the polyethylene copolymer compositionhas a high load melt index, I₂₁ of at least 150 g/10 min (≥150 g/10min), or at least 175 g/10 min (≥175 g/10 min), or at least 200 g/10 min(≥200 g/10 min), or greater than 200 g/10 min (>200 g/10 min), or atleast 225 g/10 min 225 g/10 min), or greater than 225 g/10 min (>225g/10 min), or at least 250 g/10 min (≥250 g/10 min), or greater than 250g/10 min (>250 g/10 min). In another embodiment of the disclosure, thepolyethylene copolymer composition has a high load melt index, I₂₁ offrom 175 to 1200 g/10 min, including any narrower ranges within thisrange and any values encompassed by these ranges. For example, inembodiments of the disclosure, the high load melt index, I₂₁ of thepolyethylene copolymer composition may be from 175 to 1000 g/10 min, orfrom 175 to 750 g/10 min, from 200 to 1000 g/10 min, or from 200 to 750g/10 min, or from 225 to 1000 g/10 min, or from 225 to 750 g/10 min, orfrom 250 to 1000 g/10 min, or from 250 to 750 g/10 min, or from 200 to500 g/10 min.

In embodiments of the disclosure the polyethylene copolymer compositionhas a melt flow ratio, I₂₁/I₂ of ≤60, or <60, or ≤50, or <50, or ≤45, or<40, or ≤35, or <35, or ≤30, or <30. In another embodiment of thedisclosure, the polyethylene copolymer composition has a melt flowratio, I₂₁/I₂ of from 15 to 60, including any narrower ranges withinthis range and any values encompassed by these ranges. For example, inembodiments of the disclosure, the polyethylene copolymer compositionhas a melt flow ratio, I₂₁/I₂ of from 16 to 50, or from 16 to 42, orfrom 18 to 50, or from 20 to 50, or from 22 to 50, or from 18 to 45, orfrom 18 to 40, or from 16 to 40, or from 16 to 38, or from 18 to 34, orfrom 18 to 32, or from 20 to 30.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a stress exponent, defined asLog₁₀[I₆/I₂]/Log₁₀[6.48/2.16], which is ≤1.40. In further embodiments ofthe disclosure the polyethylene copolymer composition has a stressexponent, Log₁₀[I₆/I₂]/Log₁₀[6.48/2.16] of less than 1.38, or less than1.36, or less than 1.34, or less than 1.32, or less than 1.30.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a shear viscosity at about 10⁵ s⁻¹ (240° C.) of lessthan about 10 Pa·s. In an embodiment of the disclosure, the polyethylenecopolymer composition has a shear viscosity at about 10⁵ s⁻¹ (240° C.)of from about 2 to about 10 Pa·s including any narrower ranges withinthis range and any values encompassed by these ranges. For example, inembodiments of the disclosure, the polyethylene copolymer compositionhas a shear viscosity at about 10⁵ s⁻¹ (240° C.) of from about 3 toabout 9 Pa·s, or from about 4 to about 9 Pa·s, or from about 4 to about8.5 Pa·s.

In an embodiment of the invention, the shear viscosity ratio,SVR(_(100,100000)) at 240° C. of the polyethylene copolymer compositioncan be from about 10 to about 80, including any narrower ranges withinthis range and any values encompassed by these ranges. For example, inembodiments of the disclosure, the shear viscosity ratio,SVR(_(100,100000)) at 240° C. of the polyethylene copolymer compositioncan be from about 20 to about 80, or from about 25 to about 75, or fromabout 30 to about 70, or from about 35 to about 75, or from about 30 toabout 65, or from about 30 to about 55, or from 35 to 65, or from 35 to60.

In embodiments of the invention, the polyethylene copolymer compositionor a molded article made from the polyethylene composition has a notchedIzod impact strength of at least 0.80 ft·lb/inch, or at least 0.85ft·lb/inch, or at least 0.90 ft·lb/inch, or at least 0.93 ft·lb/inch, asmeasured according to ASTM D256.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a hexane extractable value of ≤5.5 weight percent, orless than 4.5 wt %, or less than 3.5 wt %, or less than 2.5 wt %, orless than 2.0 wt %, or less than 1.5 wt %, or less than 1.0 wt %, orless than 0.5 wt %.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a composition distribution breadth index (CDBI(50)), asdetermined by temperature elution fractionation (TREF), of ≥ about 60weight percent. In further embodiments of the disclosure, thepolyethylene composition will have a CDBI(50) of greater than about 65%,or greater than about 70%, or greater than about 75%, or greater thanabout 80%, or greater than about 85%.

In an embodiment of the disclosure, the polyethylene copolymercomposition has a composition distribution breadth index (CDBI(25)), asdetermined by temperature elution fractionation (TREF), of ≥ about 55weight percent. In further embodiments of the disclosure, thepolyethylene composition will have a CDBI(25) of greater than about 60%,or greater than about 65%, or from about 55 to about 75%, or from about60 to about 75%.

In an embodiment of the disclosure, the polyethylene copolymercomposition or a molded article (or plaque) made from the polyethylenecopolymer composition, has an environment stress crack resistance ESCRCondition B at 100% of at least 3.0 hours, as measured according to ASTMD1693 (at 50° C. using 100% IGEPAL, condition B). In an embodiment ofthe disclosure, the polyethylene copolymer composition or a moldedarticle (or plaque) made from the polyethylene copolymer composition,has an environment stress crack resistance ESCR Condition B at 100% ofat least about 3.5 hours, as measured according to ASTM D1693 (at 50° C.using 100% IGEPAL, condition B). In an embodiment of the disclosure, thepolyethylene copolymer composition or a molded article (or plaque) madefrom the polyethylene copolymer composition, has an environment stresscrack resistance ESCR Condition B at 100% of at least about 4.0 hours,as measured according to ASTM D1693 (at 50° C. using 100% Igepal,condition B). In an embodiment of the disclosure, the polyethylenecopolymer composition or a molded article (or plaque) made from thepolyethylene copolymer composition, has an environment stress crackresistance ESCR Condition B at 100% of at least about 4.5 hours, asmeasured according to ASTM D1693 (at 50° C. using 100% IGEPAL, conditionB). In an embodiment of the disclosure, the polyethylene copolymercomposition or a molded article (or plaque) made from the polyethylenecopolymer composition, has an environment stress crack resistance ESCRCondition B at 100% of at least about 5.0 hours, as measured accordingto ASTM D1693 (at 50° C. using 100% IGEPAL, condition B).

In an embodiment of the disclosure, the polyethylene copolymercomposition or a molded article (or plaque) made from the polyethylenecopolymer composition, has an environment stress crack resistance ESCRCondition B at 100% of from about 3.5 to about 15 hours, as measuredaccording to ASTM D1693 (at 50° C. using 100% about IGEPAL, condition B)including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the polyethylene copolymer composition or a molded article(or plaque) made from the polyethylene copolymer composition, has anenvironment stress crack resistance ESCR Condition B at 100% of fromabout 3.5 to about 12 hours, as measured according to ASTM D1693 (at 50°C. using 100% about IGEPAL, condition B), or from about 3.5 to about 10hours, as measured according to ASTM D1693 (at 50° C. using 100% aboutIGEPAL, condition B), or from about 4.0 to about 15 hours, as measuredaccording to ASTM D1693 (at 50° C. using 100% about IGEPAL, conditionB), or from about 4.5 to about 12 hours, as measured according to ASTMD1693 (at 50° C. using 100% about IGEPAL, condition B), or from about 5to about 10 hours, as measured according to ASTM D1693 (at 50° C. using100% about IGEPAL, condition B).

The polyethylene copolymer composition of this disclosure can be madeusing any conventional blending method such as but not limited tophysical blending and in-situ blending by polymerization in multireactor systems. For example, it is possible to perform the mixing ofthe first ethylene copolymer with the second ethylene copolymer bymolten mixing of the two preformed polymers. Preferred are processes inwhich the first and second ethylene copolymers are prepared in at leasttwo sequential polymerization stages, however, both in-series or anin-parallel dual reactor process are contemplated for use in the currentdisclosure. Gas phase, slurry phase or solution phase reactor systemsmay be used, with solution phase reactor systems being preferred.

Mixed catalyst single reactor systems may also be employed to make thepolyethylene copolymer compositions of the present disclosure.

In an embodiment of the current disclosure, a dual reactor solutionpolymerization process is used as has been described in for example U.S.Pat. No. 6,372,864 and U.S. Pat. Appl. No. 20060247373A1 which areincorporated herein by reference.

Generally, the catalysts used in the current disclosure will be socalled single site catalysts based on a group 4 metal having at leastone cyclopentadienyl ligand. Examples of such catalysts which includemetallocenes, constrained geometry catalysts and phosphinimine catalystsare typically used in combination with activators selected frommethylaluminoxanes, boranes or ionic borate salts and are furtherdescribed in U.S. Pat. Nos. 3,645,992; 5,324,800; 5,064,802; 5,055,438;6,689,847; 6,114,481 and 6,063,879. Such single site catalysts aredistinguished from traditional Ziegler-Natta or Phillips catalysts whichare also well known in the art. In general, single site catalystsproduce ethylene copolymers having a molecular weight distribution(M_(w)/M_(n)) of less than about 3.0, or in some cases less than about2.5.

In embodiments of the disclosure, a single site catalyst which gives anethylene copolymer having a molecular weight distribution (M_(w)/M_(n))of less than about 3.0, or less than about 2.7, or less than about 2.5,is used in the preparation of each of the first and the second ethylenecopolymers.

In an embodiment of the disclosure, the first and second ethylenecopolymers are prepared using an organometallic complex of a group 3, 4or 5 metal that is further characterized as having a phosphinimineligand. Such a complex, when active toward olefin polymerization, isknown generally as a phosphinimine (polymerization) catalyst. Somenon-limiting examples of phosphinimine catalysts can be found in U.S.Pat. Nos. 6,342,463; 6,235,672; 6,372,864; 6,984,695; 6,063,879;6,777,509 and 6,277,931 all of which are incorporated by referenceherein.

Some non-limiting examples of metallocene catalysts can be found in U.S.Pat. Nos. 4,808,561; 4,701,432; 4,937,301; 5,324,800; 5,633,394;4,935,397; 6,002,033 and 6,489,413, which are incorporated herein byreference. Some non-limiting examples of constrained geometry catalystscan be found in U.S. Pat. Nos. 5,057,475; 5,096,867; 5,064,802;5,132,380; 5,703,187 and 6,034,021, all of which are incorporated byreference herein in their entirety.

In an embodiment of the disclosure, use of a single site catalyst thatdoes not produce long chain branching (LCB) is preferred. Hexyl (C6)branches detected by NMR are excluded from the definition of a longchain branch in the present disclosure.

In embodiments of the disclosure, the polyethylene copolymer compositionhas no long chain branching or has undetectable levels of long chainbranching.

Without wishing to be bound by any single theory, long chain branchingcan increase viscosity at low shear rates, thereby negatively impactingcycle times during the manufacture of caps and closures, such as duringthe process of compression molding. Long chain branching may bedetermined using ¹³C NMR methods and may be quantitatively assessedusing the method disclosed by Randall in Rev. Macromol. Chem. Phys. C29(2 and 3), p. 285.

In an embodiment of the disclosure, the polyethylene copolymercomposition will contain fewer than 0.3 long chain branches per 1000carbon atoms. In another embodiment of the disclosure, the polyethylenecopolymer composition will contain fewer than 0.01 long chain branchesper 1000 carbon atoms.

In an embodiment of the disclosure, the polyethylene copolymercomposition is prepared by contacting ethylene and at least onealpha-olefin with a polymerization catalyst under solution phasepolymerization conditions in at least two polymerization reactors (foran example of solution phase polymerization conditions see for exampleU.S. Pat. Nos. 6,372,864 and 6,984,695 and U.S. Patent Application20060247373A1).

In an embodiment of the disclosure, the polyethylene copolymercomposition is prepared by contacting at least one single sitepolymerization catalyst system (comprising at least one single sitecatalyst and at least one activator) with ethylene and a least onecomonomer (e.g., a C3-C8 alpha-olefin) under solution polymerizationconditions in at least two polymerization reactors.

In an embodiment of the disclosure, a group 4 single site catalystsystem, comprising a single site catalyst and an activator, is used in asolution phase dual reactor system to prepare a polyethylene copolymercomposition by polymerization of ethylene in the presence of analpha-olefin comonomer.

In an embodiment of the disclosure, a group 4 single site catalystsystem, comprising a single site catalyst and an activator, is used in asolution phase dual reactor system to prepare a polyethylene copolymercomposition by polymerization of ethylene in the presence of 1-octene.

In an embodiment of the disclosure, a group 4 phosphinimine catalystsystem, comprising a phosphinimine catalyst and an activator, is used ina solution phase dual reactor system to prepare a polyethylene copolymercomposition by polymerization of ethylene in the presence of analpha-olefin comonomer.

In an embodiment of the disclosure, a group 4 phosphinimine catalystsystem, comprising a phosphinimine catalyst and an activator, is used ina solution phase dual reactor system to prepare a polyethylene copolymercomposition by polymerization of ethylene in the presence of 1-octene.

In an embodiment of the disclosure, a solution phase dual reactor systemcomprises two solution phase reactors connected in series.

In an embodiment of the disclosure, a polymerization process to preparethe polyethylene copolymer composition comprises contacting at least onesingle site polymerization catalyst system (comprising at least onesingle site catalyst and at least one activator) with ethylene and atleast one alpha-olefin comonomer under solution polymerizationconditions in at least two polymerization reactors.

In an embodiment of the disclosure, a polymerization process to preparethe polyethylene copolymer composition comprises contacting at least onesingle site polymerization catalyst system with ethylene and at leastone alpha-olefin comonomer under solution polymerization conditions in afirst reactor and a second reactor configured in series.

In an embodiment of the disclosure, a polymerization process to preparethe polyethylene copolymer composition comprises contacting at least onesingle site polymerization catalyst system with ethylene and at leastone alpha-olefin comonomer under solution polymerization conditions in afirst reactor and a second reactor configured in series, with the atleast one alpha-olefin comonomer being fed exclusively to the firstreactor.

The production of the polyethylene copolymer composition of the presentdisclosure will typically include an extrusion or compounding step. Suchsteps are well known in the art.

The polyethylene copolymer composition can comprise further polymercomponents in addition to the first and second ethylene copolymers. Suchpolymer components include polymers made in situ or polymers added tothe polymer composition during an extrusion or compounding step.

Optionally, additives can be added to the polyethylene copolymercomposition. Additives can be added to the polyethylene copolymercomposition during an extrusion or compounding step, but other suitableknown methods will be apparent to a person skilled in the art. Theadditives can be added as is or as part of a separate polymer component(i.e. not the first or second ethylene copolymers described herein) oradded as part of a masterbatch (optionally during an extrusion orcompounding step). Suitable additives are known in the art and includebut are not-limited to antioxidants, phosphites and phosphonites,nitrones, antacids, UV light stabilizers, UV absorbers, metaldeactivators, dyes, fillers and reinforcing agents, nano-scale organicor inorganic materials, antistatic agents, lubricating agents such ascalcium stearates, slip additives such as erucamide or behenamide, andnucleating agents (including nucleators, pigments or any other chemicalswhich may provide a nucleating effect to the polyethylene copolymercomposition). The additives that can be optionally added are typicallyadded in amount of up to 20 weight percent (wt %).

One or more nucleating agent(s) may be introduced into the polyethylenecopolymer composition by kneading a mixture of the polymer, usually inpowder or pellet form, with the nucleating agent, which may be utilizedalone or in the form of a concentrate containing further additives suchas stabilizers, pigments, antistatics, UV stabilizers and fillers. Itshould be a material which is wetted or absorbed by the polymer, whichis insoluble in the polymer and of melting point higher than that of thepolymer, and it should be homogeneously dispersible in the polymer meltin as fine a form as possible (1 to 10 μm). Compounds known to have anucleating capacity for polyolefins include salts of aliphatic monobasicor dibasic acids or arylalkyl acids, such as sodium succinate, oraluminum phenylacetate; and alkali metal or aluminum salts of aromaticor alicyclic carboxylic acids such as sodium β-naphthoate, or sodiumbenzoate.

Some non-limiting examples of nucleating agents which are commerciallyavailable and which may be added to the polyethylene copolymercomposition are dibenzylidene sorbital esters (such as the products soldunder the trademark MILLAD® 3988 by Milliken Chemical and IRGACLEAR® byCiba Specialty Chemicals). Further non-limiting examples of nucleatingagents which may be added to the polyethylene copolymer compositioninclude the cyclic organic structures disclosed in U.S. Pat. No.5,981,636 (and salts thereof, such as disodium bicyclo [2.2.1] heptenedicarboxylate); the saturated versions of the structures disclosed inU.S. Pat. No. 5,981,636 (as disclosed in U.S. Pat. No. 6,465,551; Zhaoet al., to Milliken); the salts of certain cyclic dicarboxylic acidshaving a hexahydrophthalic acid structure (or “HHPA” structure) asdisclosed in U.S. Pat. No. 6,599,971 (Dotson et al., to Milliken); andphosphate esters, such as those disclosed in U.S. Pat. No. 5,342,868 andthose sold under the trade names NA-11 and NA-21 by Asahi Denka Kogyo,cyclic dicarboxylates and the salts thereof, such as the divalent metalor metalloid salts, (particularly, calcium salts) of the HHPA structuresdisclosed in U.S. Pat. No. 6,599,971. For clarity, the HHPA structuregenerally comprises a ring structure with six carbon atoms in the ringand two carboxylic acid groups which are substituents on adjacent atomsof the ring structure. The other four carbon atoms in the ring may besubstituted, as disclosed in U.S. Pat. No. 6,599,971. An example is1,2-cyclohexanedicarboxylicacid, calcium salt (CAS registry number491589-22-1). Still further non-limiting examples of nucleating agentswhich may be added to the polyethylene copolymer composition includethose disclosed in WO2015042561, WO2015042563, WO2015042562 andWO2011050042.

Many of the above described nucleating agents may be difficult to mixwith the polyethylene copolymer composition that is being nucleated andit is known to use dispersion aids, such as for example, zinc stearate,to mitigate this problem.

In an embodiment of the disclosure, the nucleating agents are welldispersed in the polyethylene copolymer composition.

In an embodiment of the disclosure, the amount of nucleating agent usedis comparatively small—from 100 to 4000 parts by million per weight(based on the weight of the polyethylene copolymer composition) so itwill be appreciated by those skilled in the art that some care must betaken to ensure that the nucleating agent is well dispersed. In anembodiment of the disclosure, the nucleating agent is added in finelydivided form (less than 50 microns, especially less than 10 microns) tothe polyethylene copolymer composition to facilitate mixing. This typeof “physical blend” (i.e. a mixture of the nucleating agent and theresin in solid form) is in an embodiment preferable to the use of a“masterbatch” of the nucleator (where the term “masterbatch” refers tothe practice of first melt mixing the additive—the nucleator, in thiscase—with a small amount of the polyethylene copolymer composition—thenmelt mixing the “masterbatch” with the remaining bulk of thepolyethylene copolymer composition).

In an embodiment of the disclosure, an additive such as nucleating agentmay be added to the polyethylene copolymer composition by way of a“masterbatch”, where the term “masterbatch” refers to the practice offirst melt mixing the additive (e.g. a nucleator) with a small amount ofthe polyethylene copolymer composition, followed by melt mixing the“masterbatch” with the remaining bulk of the polyethylene copolymercomposition.

In an embodiment of the disclosure, the polyethylene copolymercomposition further comprises a nucleating agent.

In an embodiment of the disclosure, the polyethylene copolymercomposition comprises from 20 to 4000 ppm (i.e. parts per million, basedon the total weight of the first and the second ethylene copolymers inthe polyethylene copolymer composition) of a nucleating agent.

In an embodiment of the disclosure, the polyethylene copolymercomposition further comprises a nucleating agent which is a salt of adicarboxylic acid compound. A dicarboxylic acid compound is hereindefined as an organic compound containing two carboxyl (—COOH)functional groups. A salt of a dicarboxylic acid compound then willcomprise one or more suitable cationic counter cations, preferably metalcations, and an organic compound having two anionic carboxylate (—COO⁻)groups.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in the formation of molded articles. Such articlesmay be formed by compression molding, continuous compression molding,injection molding or blow molding. Such articles include, for example,caps, screw caps, and closures, including hinged and tethered versionsthereof, for bottles, containers, pouches, pill bottles, fitments,pharmaceutical bottles and the like.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in the formation of a fitment for bottles, pouchesor the like.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in flexible packaging.

In an embodiment of the disclosure the polyethylene copolymercomposition is used in the formation of films, such as for example,blown film, cast film and lamination or extrusion film or extrusioncoating as well as stretch film. Processes to make such films from apolymer are well known to persons skilled in the art.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in an extrusion coating film layer.

In an embodiment of the disclosure the polyethylene copolymercomposition is used in the formation of one or more than one film layerwhich is part of a multilayer layer film or film structure. Processes tomakes such multilayer films or film structures are well known to personsskilled in the art.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in the formation of any closure, of any suitabledesign and dimensions for use in any hot filling process (or asepticfilling process) for filling any suitable bottle, container or the like.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in the formation of a closure for bottles,containers, pouches and the like. For example, closures for bottlesformed by continuous compression molding, or injection molding arecontemplated. Such closures include, for example, caps, hinged caps,screw caps, hinged screw caps, snap-top caps, hinged snap-top caps, andoptionally hinged closures for bottles, containers, pouches and thelike.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in the formation of a fitment for a pouch, containeror the like.

In an embodiment of the disclosure, the polyethylene copolymercomposition is used in the formation of molded articles. For example,articles formed by continuous compression molding and injection moldingare contemplated. Such articles include, for example, caps, screw caps,and closures for bottles.

Closures

The terms “cap” and “closure” are used interchangeably in the currentdisclosure, and both connote any suitably shaped molded article forenclosing, sealing, closing or covering etc., a suitably shaped opening,a suitably molded aperture, an open necked structure or the like used incombination with a container, a bottle, a jar, a pouch and the like.

Closures include one piece closures or closures comprising more than onepiece.

In an embodiment of the disclosure, the polyethylene copolymercompositions described above are used in the formation of a closure.

In an embodiment of the disclosure, the polyethylene copolymercompositions described above are used in the formation of a one piececlosure.

In an embodiment of the disclosure, the polyethylene copolymercompositions described above are used in the formation of a closurehaving a tamper evident band (a TEB).

In an embodiment of the disclosure, the polyethylene copolymercomposition described above are used in the formation of a closure forbottles, containers, pouches and the like. For example, closures forbottles formed by compression molding or injection molding arecontemplated. Such closures include, for example, hinged caps, hingedscrew caps, hinged snap-top caps, and hinged closures for bottles,containers, pouches and the like.

In an embodiment of the disclosure, the polyethylene copolymercompositions described above are used in the formation of a bottleclosure assembly comprising a cap portion, a tether portion and aretaining means portion.

In an embodiment of the disclosure, a closure (or cap) is a screw capfor a bottle, container, pouch and the like.

In an embodiment of the disclosure, a closure (or cap) is a snap closurefor a bottle, container, pouch and the like.

In an embodiment of the disclosure, a closure (or cap) comprises a hingemade of the same material as the rest of the closure (or cap).

In an embodiment of the disclosure, a closure (or cap) is a hingedclosure.

In an embodiment of the disclosure, a closure (or cap) is a hingedclosure for bottles, containers, pouches and the like.

In an embodiment of the disclosure, a closure (or cap) is for retort,hot fill, aseptic fill and cold fill applications.

In an embodiment of the disclosure, a closure (or cap) is a flip-tophinge closure, such as a flip-top hinge closure for use on a plasticketchup bottle or similar containers containing foodstuffs.

When a closure is a hinged closure, it comprises a hinged component andgenerally consists of at least two bodies which are connected by atleast one thinner section that acts as a so called “living hinge”allowing the at least two bodies to bend from an initially moldedposition. The thinner section or sections may be continuous or web-like,wide or narrow.

A useful closure (for bottles, containers and the like) is a hingedclosure and may consist of two bodies joined to each other by at leastone thinner bendable portion (e.g. the two bodies can be joined by asingle bridging portion, or more than one bridging portion, or by awebbed portion, etc.). A first body may contain a dispensing hole andwhich may snap onto or screw onto a container to cover a containeropening (e.g. a bottle opening) while a second body may serve as a snapon lid which may mate with the first body.

The caps and closures, of which hinged caps and closures and screw capsare a subset, can be made according to any known method, including forexample injection molding and compression molding techniques that arewell known to persons skilled in the art. Hence, in an embodiment of thedisclosure a closure (or cap) comprising the polyethylene copolymercomposition (defined above) is prepared with a process comprising atleast one compression molding step and/or at least one injection moldingstep.

In one embodiment, the caps and closures (including single piece ormulti-piece variants and hinged variants) comprise the polyethylenecopolymer composition described above which have good barrierproperties, as well as good processability. Hence the closures and capsof this embodiment are well suited for sealing bottles, containers andthe like, for examples bottles that may contain spoilable (for example,due to contact with oxygen) liquids or foodstuffs, including but notlimited to liquids that are under an appropriate pressure (i.e.carbonated beverages or appropriately pressurized drinkable liquids).

The closures and caps may also be used for sealing bottles containingdrinkable water or non-carbonated beverages (e.g. juice). Otherapplications, include caps and closures for bottles, containers andpouches containing foodstuffs, such as for example ketchup bottles andthe like.

The closures and caps may be one-piece closures or two piece closurescomprising a closure and a liner.

The closures and caps may also be of multilayer design, wherein theclosure of cap comprises at least two layers at least one of which ismade of the polyethylene blends described herein.

In an embodiment of the disclosure the closure is made by continuouscompression molding.

In an embodiment of the disclosure the closure is made by injectionmolding.

A closure as described in the present disclosure may be a closuresuitable for use in a container sealing process comprising one of moresteps in which the closure comes into contact with a liquid at elevatedtemperatures, such as a hot fill processes, and in some cases an asepticfill processes. Such closures and processes are described in for exampleCA Pat. Appl. Nos 2,914,353; 2,914,354; and 2,914,315.

In an embodiment of the disclosure, a closure made is a PCO 1881 CSDclosure, having a weight of about 2.15 grams and having the followingdimensions: Closure height (not including Tamper Ring)=about 10.7 mm;Closure height with Tamper Ring=about 15.4 mm; Outside diameter @ 4mm=about 29.6 mm; Thread diameter=about 25.5 mm; Bump sealdiameter=about 24.5 mm; Bump seal thickness=about 0.7 mm; Bump sealheight to center of olive=about 1.5 mm; Bore seal diameter=about 22.5mm; Bore seal thickness=about 0.9 mm; Bore height to center ofolive=about 1.6 mm; Top panel thickness=about 1.2 mm; Tamper bandundercut diameter=about 26.3 mm; Thread depth=about 1.1 mm; Threadpitch=about 2.5 mm; Thread Root @ 4 mm=27.4 mm.

In an embodiment of the disclosure, a closure is made using an injectionmolding process to prepare a PCO 1881 CSD closure, having a weight ofabout 2.15 grams and having the following dimensions: Closure height(not including Tamper Ring)=about 10.7 mm; Closure height with TamperRing=about 15.4 mm; Outside diameter @ 4 mm=about 29.6 mm; Threaddiameter=about 25.5 mm; Bump seal diameter=about 24.5 mm; Bump sealthickness=about 0.7 mm; Bump seal height to center of olive=about 1.5mm; Bore seal diameter=about 22.5 mm; Bore seal thickness=about 0.9 mm;Bore height to center of olive=about 1.6 mm; Top panel thickness=about1.2 mm; Tamper band undercut diameter=about 26.3 mm; Thread depth=about1.1 mm; Thread pitch=about 2.5 mm; Thread Root @ 4 mm=27.4 mm.

In an embodiment of the disclosure, a closure is made using a continuouscompression molding process to prepare a PCO 1881 CSD closure, having aweight of about 2.15 grams and having the following dimensions: Closureheight (not including Tamper Ring)=about 10.7 mm; Closure height withTamper Ring=about 15.4 mm; Outside diameter @ 4 mm=about 29.6 mm; Threaddiameter=about 25.5 mm; Bump seal diameter=about 24.5 mm; Bump sealthickness=about 0.7 mm; Bump seal height to center of olive=about 1.5mm; Bore seal diameter=about 22.5 mm; Bore seal thickness=about 0.9 mm;Bore height to center of olive=about 1.6 mm; Top panel thickness=about1.2 mm; Tamper band undercut diameter=about 26.3 mm; Thread depth=about1.1 mm; Thread pitch=about 2.5 mm; Thread Root @ 4 mm=27.4 mm.

In embodiments of the disclosure, a closure is made using a moldingprocess to prepare a PCO 1881 CSD closure having an oxygen transmissionrate, OTR of ≤0.0035 cm³/closure/day, or ≤0.0032 cm³/closure/day, or≤0.0030 cm³/closure/day, or ≤0.0029 cm³/closure/day, ≤0.0028cm³/closure/day, or ≤0.0027 cm³/closure/day.

In an embodiment of the disclosure, a closure is made using a continuouscompression molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of ≤0.0035 cm³/closure/day, or ≤0.0032cm³/closure/day, or ≤0.0030 cm³/closure/day, or ≤0.0029 cm³/closure/day,≤0.0028 cm³/closure/day, or ≤0.0027 cm³/closure/day.

In an embodiment of the disclosure, the closure is made using aninjection molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of ≤0.0035 cm³/closure/day, or ≤0.0032cm³/closure/day, or ≤0.0030 cm³/closure/day, or ≤0.0029 cm³/closure/day,≤0.0028 cm³/closure/day, or ≤0.0027 cm³/closure/day.

In embodiments of the disclosure, a closure is made using a moldingprocess to prepare a PCO 1881 CSD closure having an oxygen transmissionrate, OTR of from 0.0016 to 0.0035 cm³/closure/day including anynarrower ranges within this range and any values encompassed by theseranges. For example, in embodiments of the disclosure, a closure is madeusing a molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of from 0.0018 to 0.0034 cm³/closure/day,or from 0.0018 to 0.0032 cm³/closure/day, or from 0.0018 to 0.0030cm³/closure/day, or from 0.0020 to 0.0030 cm³/closure/day.

In an embodiment of the disclosure, a closure is made using a continuouscompression molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of from 0.0016 to 0.0035 cm³/closure/dayincluding any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a closure is made using a continuous compression moldingprocess to prepare a PCO 1881 CSD closure having an oxygen transmissionrate, OTR of from 0.0018 to 0.0034 cm³/closure/day, or from 0.0018 to0.0032 cm³/closure/day, or from 0.0018 to 0.0030 cm³/closure/day, orfrom 0.0020 to 0.0030 cm³/closure/day.

In an embodiment of the disclosure, a closure is made using an injectionmolding process to prepare a PCO 1881 CSD closure having a having anoxygen transmission rate, OTR of from 0.0016 to 0.0035 cm³/closure/dayincluding any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a closure is made using an injection molding process toprepare a PCO 1881 CSD closure having a having an oxygen transmissionrate, OTR of from 0.0018 to 0.0034 cm³/closure/day, or from 0.0018 to0.0032 cm³/closure/day, or from 0.0018 to 0.0030 cm³/closure/day, orfrom 0.0020 to 0.0030 cm³/closure/day.

Cast (and Lamination) Film

In an embodiment of the disclosure, the polyethylene copolymercompositions described above are used in the formation of a cast film orlaminate film.

Cast films are extruded from a flat die onto a chilled roll or a nippedroll, optionally, with a vacuum box and/or air-knife. The films may bemonolayer or coextruded multi-layer films obtained by various extrusionthrough a single or multiple dies. The resultant films may be the usedas-is or may be laminated to other films or substrates, for example bythermal, adhesive lamination or direct extrusion onto a substrate. Theresultant films and laminates may be subjected to other formingoperations such as embossing, stretching, thermoforming. Surfacetreatments such as corona may be applied and the films may be printed.In the cast film extrusion process, a thin film is extruded through aslit onto a chilled, highly polished turning roll, where it is quenchedfrom one side. The speed of the roller controls the draw ratio and finalfilm thickness. The film is then sent to a second roller for cooling onthe other side. Finally, it passes through a system of rollers and iswound onto a roll. In another embodiment, two or more thin films arecoextruded through two or more slits onto a chilled, highly polishedturning roll, the coextruded film is quenched from one side. The speedof the roller controls the draw ratio and final coextruded filmthickness. The coextruded film is then sent to a second roller forcooling on the other side. Finally, it passes through a system ofrollers and is wound onto a roll.

In an embodiment, the cast film product may further be laminated one ormore layers into a multilayer structure.

The cast films and laminates may be used in a variety of purposes, forexample food packaging (dry foods, fresh foods, frozen foods, liquids,processed foods, powders, granules), for packaging of detergents,toothpaste, towels, for labels and release liners. The films may also beused in unitization and industrial packaging, notably in stretch films.The films may also be suitable in hygiene and medical applications, forexample in breathable and non-breathable films used in diapers, adultincontinence products, feminine hygiene products, ostomy bags. Finally,cast films may also be used in tapes and artificial turf applications.

In embodiments of the disclosure, a film or film layer has a normalizedoxygen transmission rate, OTR of ≤130 cm³/100 in²/day, or ≤125 cm³/100in²/day, or ≤120 cm³/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized oxygen transmission rate, OTR of ≤130 cm³/100in²/day, or ≤125 cm³/100 in²/day, or ≤120 cm³/100 in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized oxygen transmission rate, OTR of ≤130 cm³/100 in²/day, or≤125 cm³/100 in²/day, or ≤120 cm³/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized oxygen transmission rate, OTR of ≤130 cm³/100 in²/day, or≤125 cm³/100 in²/day, or ≤120 cm³/100 in²/day.

In embodiments of the disclosure, a film or film layer has a normalizedoxygen transmission rate, OTR of from 50 to 140 cm³/100 in²/day,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a film or film layer has a normalized oxygen transmissionrate, OTR of from 60 to 130 cm³/100 in²/day, or from 70 to 130 cm³/100in²/day, or from 70 to 120 cm³/100 in²/day, or from 80 to 130 cm³/100in²/day, or from 80 to 120 cm³/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized oxygen transmission rate, OTR of from 50 to 140cm³/100 in²/day, including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, a compression molded film or film layer has a normalizedoxygen transmission rate, OTR of from 60 to 130 cm³/100 in²/day, or from70 to 130 cm³/100 in²/day, or from 70 to 120 cm³/100 in²/day, or from 80to 130 cm³/100 in²/day, or from 80 to 120 cm³/100 in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized oxygen transmission rate, OTR of from 50 to 140 cm³/100in²/day, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a cast film or film layer has a normalized oxygentransmission rate, OTR of from 60 to 130 cm³/100 in²/day, or from 70 to130 cm³/100 in²/day, or from 70 to 120 cm³/100 in²/day, or from 80 to130 cm³/100 in²/day, or from 80 to 120 cm³/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized oxygen transmission rate, OTR of from 50 to 140 cm³/100in²/day, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a lamination film or film layer has a normalized oxygentransmission rate, OTR of from 60 to 130 cm³/100 in²/day, or from 70 to130 cm³/100 in²/day, or from 70 to 120 cm³/100 in²/day, or from 80 to130 cm³/100 in²/day, or from 80 to 120 cm³/100 in²/day.

In embodiments of the disclosure, a film or film layer has a normalizedwater vapor transmission rate, WVTR of ≤0.340 g/100 in²/day, or ≤0.320g/100 in²/day, or ≤0.310 g/100 in²/day, or ≤0.300 g/100 in²/day, or≤0.298 g/100 in²/day, or ≤0.296 g/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized water vapor transmission rate, WVTR of ≤0.340g/100 in²/day, or ≤0.320 g/100 in²/day, or ≤0.310 g/100 in²/day, or≤0.300 g/100 in²/day, or ≤0.298 g/100 in²/day, or ≤0.296 g/100 in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized water vapor transmission rate, WVTR of ≤0.340 g/100 in²/day,or ≤0.320 g/100 in²/day, or ≤0.310 g/100 in²/day, or ≤0.300 g/100in²/day, or ≤0.298 g/100 in²/day, or ≤0.296 g/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized water vapor transmission rate, WVTR of ≤0.340 g/100 in²/day,or ≤0.320 g/100 in²/day, or ≤0.310 g/100 in²/day, or ≤0.300 g/100in²/day, or ≤0.298 g/100 in²/day, or ≤0.296 g/100 in²/day.

In embodiments of the disclosure, a film or film layer has a normalizedwater vapor transmission rate, WVTR of from 0.150 to 0.340 g/100 in²/dayincluding any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a film or film layer has a normalized water vaportransmission rate, WVTR of from 0.160 to 0.340 g/100 in²/day, or from0.170 to 0.340 g/100 in²/day, or from 0.170 to 0.330 g/100 in²/day, orfrom 0.180 to 0.330 g/100 in²/day, or from 0.180 to 0.320 g/100 in²/day,or from 0.190 to 0.320 g/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized water vapor transmission rate, WVTR of from 0.150to 0.340 g/100 in²/day including any narrower ranges within this rangeand any values encompassed by these ranges. For example, in embodimentsof the disclosure, a compression molded film or film layer has anormalized water vapor transmission rate, WVTR of from 0.160 to 0.340g/100 in²/day, or from 0.170 to 0.340 g/100 in²/day, or from 0.170 to0.330 g/100 in²/day, or from 0.180 to 0.330 g/100 in²/day, or from 0.180to 0.320 g/100 in²/day, or from 0.190 to 0.320 g/100 in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized water vapor transmission rate, WVTR of from 0.150 to 0.340g/100 in²/day including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, a cast film or film layer has a normalized water vaportransmission rate, WVTR of from 0.160 to 0.340 g/100 in²/day, or from0.170 to 0.340 g/100 in²/day, or from 0.170 to 0.330 g/100 in²/day, orfrom 0.180 to 0.330 g/100 in²/day, or from 0.180 to 0.320 g/100 in²/day,or from 0.190 to 0.320 g/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized water vapor transmission rate, WVTR of from 0.150 to 0.340g/100 in²/day including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, a lamination film or film layer has a normalized water vaportransmission rate, WVTR of from 0.160 to 0.340 g/100 in²/day, or from0.170 to 0.340 g/100 in²/day, or from 0.170 to 0.330 g/100 in²/day, orfrom 0.180 to 0.330 g/100 in²/day, or from 0.180 to 0.320 g/100 in²/day,or from 0.190 to 0.320 g/100 in²/day.

Further non-limiting details of the disclosure are provided in thefollowing examples. The examples are presented for the purposes ofillustrating selected embodiments of this disclosure, it beingunderstood that the examples presented do not limit the claimspresented.

EXAMPLES General Polymer Characterization Methods

Prior to testing, each specimen was conditioned for at least 24 hours at23±2° C. and 50±10% relative humidity and subsequent testing wasconducted at 23±2° C. and 50±10% relative humidity. Herein, the term“ASTM conditions” refers to a laboratory that is maintained at 23±2° C.and 50±10% relative humidity; and specimens to be tested wereconditioned for at least 24 hours in this laboratory prior to testing.ASTM refers to the American Society for Testing and Materials.

Density was determined using ASTM D792-13 (Nov. 1, 2013).

Melt index was determined using ASTM D1238 (Aug. 1, 2013). Melt indexes,I₂, I₆, I₁₀ and I₂₁ were measured at 190° C., using weights of 2.16 kg,6.48 kg, 10 kg and a 21.6 kg respectively. Herein, the term “stressexponent” or its acronym “S.Ex.”, is defined by the followingrelationship: S.Ex.=log (I₆/I₂)/log(6480/2160); wherein I₆ and I₂ arethe melt flow rates measured at 190° C. using 6.48 kg and 2.16 kg loads,respectively.

M_(n), M_(w), and M_(z) (g/mol) were determined by high temperature GelPermeation Chromatography (GPC) with differential refractive index (DRI)detection using universal calibration (e.g. ASTM-D6474-99). GPC data wasobtained using an instrument sold under the trade name “Waters 150c”,with 1,2,4-trichlorobenzene as the mobile phase at 140° C. The sampleswere prepared by dissolving the polymer in this solvent and were runwithout filtration. Molecular weights are expressed as polyethyleneequivalents with a relative standard deviation of 2.9% for the numberaverage molecular weight (“Mn”) and 5.0% for the weight averagemolecular weight (“Mw”). The molecular weight distribution (MWD) is theweight average molecular weight divided by the number average molecularweight, M_(w)/M_(n). The z-average molecular weight distribution isM_(z)/M_(n). Polymer sample solutions (1 to 2 mg/mL) were prepared byheating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating on awheel for 4 hours at 150° C. in an oven. The antioxidant2,6-di-tert-butyl-4-methylphenol (BHT) was added to the mixture in orderto stabilize the polymer against oxidative degradation. The BHTconcentration was 250 ppm. Sample solutions were chromatographed at 140°C. on a PL 220 high-temperature chromatography unit equipped with fourSHODEX® columns (HT803, HT804, HT805 and HT806) using TCB as the mobilephase with a flow rate of 1.0 mL/minute, with a differential refractiveindex (DRI) as the concentration detector. BHT was added to the mobilephase at a concentration of 250 ppm to protect the columns fromoxidative degradation. The sample injection volume was 200 mL. The rawdata were processed with CIRRUS® GPC software. The columns werecalibrated with narrow distribution polystyrene standards. Thepolystyrene molecular weights were converted to polyethylene molecularweights using the Mark-Houwink equation, as described in the ASTMstandard test method D6474.

High temperature GPC equipped with an online FTIR detector (GPC-FTIR)was used to measure the comonomer content as the function of molecularweight.

Primary melting peak (° C.), heat of fusion (J/g) and crystallinity (%)was determined using differential scanning calorimetry (DSC) as follows:the instrument was first calibrated with indium; after the calibration,a polymer specimen is equilibrated at 0° C. and then the temperature wasincreased to 200° C. at a heating rate of 10° C./min; the melt was thenkept isothermally at 200° C. for five minutes; the melt was then cooledto 0° C. at a cooling rate of 10° C./min and kept at 0° C. for fiveminutes; the specimen was then heated to 200° C. at a heating rate of10° C./min. The DSC Tm, heat of fusion and crystallinity are reportedfrom the 2^(nd) heating cycle.

The short chain branch frequency (SCB per 1000 carbon atoms) of thepolyethylene composition was determined by Fourier Transform InfraredSpectroscopy (FTIR) as per the ASTM D6645-01 method. A Thermo-Nicolet750 Magna-IR Spectrophotometer equipped with OMNIC® version 7.2asoftware was used for the measurements. Unsaturations in thepolyethylene composition were also determined by Fourier TransformInfrared Spectroscopy (FTIR) as per ASTM D3124-98.

Hexane extractables were determined according to ASTM D5227.

Shear viscosity was measured by using a Kayeness WinKARS CapillaryRheometer (model #D5052M-115). For the shear viscosity at lower shearrates, a die having a die diameter of 0.06 inch and L/D ratio of 20 andan entrance angle of 180 degrees was used. For the shear viscosity athigher shear rates, a die having a die diameter of 0.012 inch and L/Dratio of 20 was used.

The Shear Viscosity Ratio as the term is used in the present disclosureis defined as: η₁₀₀/η₁₀₀₀₀₀ at 240° C. The processability indicator isdefined as 100/η₁₀₀₀₀₀. The η₁₀₀ is the melt shear viscosity at theshear rate of 100 s⁻¹ and the η₁₀₀₀₀₀ is the melt shear viscosity at theshear rate of 100000 s⁻¹ measured at 240° C.

The “processability indicator” as used herein is defined as:processability Indicator=100/η(10⁵ s⁻¹, 240° C.); where η is the shearviscosity measured at 10⁵ 1/s at 240° C.

Dynamic mechanical analyses were carried out with a rheometer, namelyRheometrics Dynamic Spectrometer (RDS-II) or Rheometrics SR5 or ATSStresstech, on compression molded samples under nitrogen atmosphere at190° C., using 25 mm diameter cone and plate geometry. The oscillatoryshear experiments were done within the linear viscoelastic range ofstrain (10% strain) at frequencies from 0.05 to 100 rad/s. The values ofstorage modulus (G′), loss modulus (G″), complex modulus (G*) andcomplex viscosity (η*) were obtained as a function of frequency. Thesame rheological data can also be obtained by using a 25 mm diameterparallel plate geometry at 190° C. under nitrogen atmosphere. The Zeroshear viscosity is estimated using the Ellis model, i.e.η(ω)=η₀/(1+τ/τ_(1/2))^(α-1), where η₀ is the zero shear viscosity.τ_(1/2) is the value of the shear stress at which η=η₀/2 and α is one ofthe adjustable parameters. The Cox-Merz rule is assumed to be applicablein the present disclosure. The SHI(1,100) value is calculated accordingto the methods described in WO 2006/048253 and WO 2006/048254.

The DRI, is the “dow rheology index”, and is defined by the equation:DRI=[365000(τ₀/η₀)−1]/10, wherein τ₀ is the characteristic relaxationtime of the polyethylene and η₀ is the zero shear viscosity of thematerial. The DRI is calculated by least squares fit of the rheologicalcurve (dynamic complex viscosity versus applied frequency e.g. 0.01-100rads/s) as described in U.S. Pat. No. 6,114,486 with the followinggeneralized Cross equation, i.e. η(ω)=η₀/[1+(ωτ₀)^(n)]; wherein n is thepower law index of the material, η(ω) and ω are the measured complexviscosity and applied frequency data respectively. When determining theDRI, the zero shear viscosity, η₀ used was estimated with the Ellismodel, rather than the Cross model.

The crossover frequency is the frequency at which storage modulus (G′)and loss modulus (G″) curves cross with each other, while G′@G″=500 Pais the storage modulus at which the loss modulus (G″) is at 500 Pa.

To determine CDBI(50), a solubility distribution curve is firstgenerated for the polyethylene composition. This is accomplished usingdata acquired from the TREF technique. This solubility distributioncurve is a plot of the weight fraction of the copolymer that issolubilized as a function of temperature. This is converted to acumulative distribution curve of weight fraction versus comonomercontent, from which the CDBI(50) is determined by establishing theweight percentage of a copolymer sample that has a comonomer contentwithin 50% of the median comonomer content on each side of the median(See WO 93/03093 and U.S. Pat. No. 5,376,439). Those skilled in the artwill understand that a calibration curve is required to convert a TREFelution temperature to comonomer content, i.e. the amount of comonomerin the polyethylene composition fraction that elutes at a specifictemperature. The generation of such calibration curves are described inthe prior art, e.g. Wild, et al., J. Polym. Sci., Part B, Polym. Phys.,Vol. 20 (3), pages 441-455: hereby fully incorporated by reference. TheCDBI(25) is determined by establishing the weight percentage of acopolymer sample that has a comonomer content within 25% of the mediancomonomer content on each side of the median.

The temperature rising elution fractionation (TREF) method used hereinwas as follows. Polymer samples (50 to 150 mg) were introduced into thereactor vessel of a crystallization-TREF unit (Polymer Char, ValenciaTechnology Park, Gustave Eiffel, 8, Paterna, E-46980 Valencia, Spain)equipped with an IR detector. The reactor vessel was filled with 20 to40 ml 1,2,4-trichlorobenzene (TCB), and heated to the desireddissolution temperature (e.g., 150° C.) for 1 to 3 hours. The solution(0.5 to 1.5 ml) was then loaded into the TREF column filled withstainless steel beads. After equilibration at a given stabilizationtemperature (e.g., 110° C.) for 30 to 45 minutes, the polymer solutionwas allowed to crystallize with a temperature drop from thestabilization temperature to 30° C. (0.1 or 0.2° C./minute). Afterequilibrating at 30° C. for 30 minutes, the crystallized sample waseluted with TCB (0.5 or 0.75 mL/minute) with a temperature ramp from 30°C. to the stabilization temperature (0.25 or 1.0° C./minute). The TREFcolumn was cleaned at the end of the run for 30 minutes at thedissolution temperature. The data were processed using Polymer Charsoftware, EXCEL® spreadsheet and TREF software developed in-house. UsingPolymer Char software a TREF distribution curve was generated as thepolyethylene composition was eluted from the TREF column, i.e. a TREFdistribution curve is a plot of the quantity (or intensity) ofpolyethylene composition eluting from the column as a function of TREFelution temperature. The crystallization-TREF was operated in the TREFmode, which generated the chemical composition of the polymer sample asa function of elution temperature, the Co/Ho ratio(Copolymer/Homopolymer ratio), the CDBI (the Composition DistributionBreadth Index), i.e. CDBI(50) and CDBI(25), the location of a hightemperature elution peak (in ° C.) and the approximate amount of a highdensity fraction (a “HD fraction”, in weight percent) which elutes at atemperature of from 95 to 105° C.

Plaques molded from the polyethylene copolymer compositions were testedaccording to the following ASTM methods: Bent Strip Environmental StressCrack Resistance (ESCR) at Condition B at 100% IGEPAL at 50° C., ASTMD1693; notched Izod impact properties, ASTM D256; Flexural Properties,ASTM D 790; Tensile properties, ASTM D 638; Vicat softening point, ASTMD 1525; Heat deflection temperature, ASTM D 648.

Examples of the polyethylene copolymer compositions were produced in adual reactor solution polymerization process in which the contents ofthe first reactor flow into the second reactor. This in-series “dualreactor” process produces an “in-situ” polyethylene blend (i.e., thepolyethylene composition). Note, that when an in-series reactorconfiguration is used, un-reacted ethylene monomer, and un-reactedalpha-olefin comonomer present in the first reactor, will flow into thedownstream second reactor for further polymerization.

In the present inventive examples, although no co-monomer is feeddirectly to the downstream second reactor, an ethylene copolymer isnevertheless formed in second reactor due to the significant presence ofun-reacted 1-octene flowing from the first reactor to the second reactorwhere it is copolymerized with ethylene. Each reactor is sufficientlyagitated to give conditions in which components are well mixed. Thevolume of the first reactor was 12 liters and the volume of the secondreactor was 22 liters. These are the pilot plant scales. The firstreactor was operated at a pressure of 10,500 to 35,000 kPa and thesecond reactor was operated at a lower pressure to facilitate continuousflow from the first reactor to the second. The solvent employed wasmethylpentane. The process operates using continuous feed streams. Thecatalyst employed in the dual reactor solution process experiments was aphosphinimine catalyst, which was a titanium complex having aphosphinimine ligand ((tert-butyl)₃P=N), a cyclopentadienide ligand (Cp)and two activatable ligands (chloride ligands; note: “activatableligands” are removed, by for example electrophilic abstraction using aco-catalyst or activator to generate an active metal center). A boronbased co-catalyst (Ph₃CB(C₆F₅)₄) was used in approximatelystoichiometric amounts relative to the titanium complex. Commerciallyavailable methylaluminoxane (MAO) was included as a scavenger at anAl:Ti of about 40:1. In addition,2,6-di-tert-butylhydroxy-4-ethylbenzene was added to scavenge freetrimethylaluminum within the MAO in a ratio of Al:OH of about 0.5:1. Thepolymerization conditions used to make the inventive polyethylenecopolymer compositions are provided in Table 1.

The polyethylene copolymer compositions of Examples 1 and 2 are madeusing a single site phosphinimine catalyst in a dual reactor solutionprocess as described above.

As can be seen in FIG. 1, the inventive Examples 1 and 2 have a bimodalmolecular weight distribution or profile in a GPC analysis (there is amain peak area, but it is flanked by a shoulder area in the GPCchromatograph).

Comparative polyethylene copolymer compositions, Examples 3, 4 and 5were prepared in a dual reactor solution polymerization process using aphosphinimine catalyst, as described in co-pending CA Pat. ApplicationNo. 3,028,157.

Non-nucleated and nucleated Inventive and as well Comparativepolyethylene composition properties are provided in Table 2. Thenucleated Inventive resins (Examples 1 and 2) and the nucleatedComparative resins (Examples 3-5) which are denoted in the Tables withthe symbol “*”, were prepared in the following manner. A 4% (by weight)masterbatch of HYPERFORM® HPN-20E nucleating agent from MillikenChemical was first prepared. This masterbatch also contained 1% (byweight) of DHT-4V (aluminium magnesium carbonate hydroxide) from KisumaChemicals. The base resin and the nucleating agent masterbatch were thenmelt blended using a Coperion ZSK 26 co-rotating twin screw extruderwith an L/D of 32:1 to give a polyethylene composition having 1200 partsper million (ppm) of the HYPERFORM HPN-20E nucleating agent present(based on the weight of the polyethylene composition). The extruder wasfitted with an underwater pelletizer and a Gala spin dryer. Thematerials were co-fed to the extruder using gravimetric feeders toachieve the desired nucleating agent level. The blends were compoundedusing a screw speed of 200 rpm at an output rate of 15-20 kg/hour and ata melt temperature of 225-230° C.

Some calculated properties for the first ethylene copolymer and thesecond ethylene copolymer present in each of the inventive polyethylenecopolymer compositions (Examples 1 and 2) are provided in Table 3 (see“Polymerization Reactor Modeling” below for methods of calculating theseproperties). For comparison purposes, Table 3 also includes somecalculated properties for the first and second ethylene copolymerspresent in the comparative polyethylene compositions of Examples 3-5.

The properties of pressed plaques made from non-nucleated and nucleatedinventive polyethylene copolymer compositions as well as comparativecompositions are provided in Table 4.

Polymerization Reactor Modeling

For multicomponent (or bimodal resins) polyethylene polymers with verylow comonomer content, it can be difficult to reliably estimate theshort chain branching (and subsequently polyethylene resin density bycombining other information) of each polymer component by mathematicaldeconvolution of GPC-FTIR data, as was done in for example U.S. Pat. No.8,022,143. Instead, the M_(w), M_(n), M_(z), M_(w)/M_(n) and the shortchain branching per thousand carbons (SCB/1000 C) of the first andsecond copolymers were calculated herein, by using a reactor modelsimulation using the input conditions which were employed for actualpilot scale run conditions (for references on relevant reactor modelingmethods, see “Copolymerization” by A. Hamielec, J. MacGregor, and A.Penlidis in Comprehensive Polymer Science and Supplements, volume 3,Chapter 2, page 17, Elsevier, 1996 and “Copolymerization of Olefins in aSeries of Continuous Stirred-Tank Slurry-Reactors using HeterogeneousZiegler-Natta and Metallocene Catalysts. I. General Dynamic MathemacialModel” by J. B. P Soares and A. E. Hamielec in Polymer ReactionEngineering, 4(2&3), p 153, 1996.) This type of model is consideredreliable for the estimate of comonomer (e.g. 1-octene) content even atlow comonomer incorporation levels, since the ethylene conversion,ethylene input flow and comonomer input flow can be obtained directlyfrom the experimental conditions and because the reactive ratio (seebelow) can be reliably estimated for the catalyst system used in thepresent disclosure. For clarity the “monomer” or “monomer 1” representethylene, while the terms “comonomer” or “monomer 2”, represent1-octene.

The model takes for input the flow of several reactive species (e.g.catalyst, monomer such as ethylene, comonomer such as 1-octene,hydrogen, and solvent) going to each reactor, the temperature (in eachreactor), and the conversion of monomer (in each reactor), andcalculates the polymer properties (of the polymer made in each reactor,i.e. the first and second ethylene copolymers) using a terminal kineticmodel for continuously stirred tank reactors (CSTRs) connected inseries. The “terminal kinetic model” assumes that the kinetics dependupon the monomer unit within the polymer chain on which the activecatalyst site is located (see “Copolymerization” by A. Hamielec, J.MacGregor, and A. Penlidis in Comprehensive Polymer Science andSupplements, volume 3, Chapter 2, page 17, Elsevier, 1996). In themodel, the copolymer chains are assumed to be of reasonably largemolecular weight to ensure that the statistics of monomer/comonomer unitinsertion at the active catalyst center is valid and thatmonomers/comonomers consumed in routes other than propagation arenegligible. This is known as the “long chain” approximation.

The terminal kinetic model for polymerization includes reaction rateequations for activation, initiation, propagation, chain transfer, anddeactivation pathways. This model solves the steady-state conservationequations (e.g. the total mass balance and heat balance) for thereactive fluid which comprises the reactive species identified above.

The total mass balance for a generic CSTR with a given number of inletsand outlets is given by:

0=Σ_(i) {dot over (m)} _(i)  (1)

where {dot over (m)}_(i) represents the mass flow rate of individualstreams with index i indicating the inlet and outlet streams.

Equation (1) can be further expanded to show the individual species andreactions:

$\begin{matrix}{0 = {\frac{\sum_{i}^{m{\overset{.}{x}}_{ij}}{/M_{i}}}{\rho_{mix}V} + {R_{j}/\rho_{mix}}}} & (2)\end{matrix}$

where M_(i) is the average molar weight of the fluid inlet or outlet(I), x_(ij) is the mass fraction of species j in stream i, μ_(mix) isthe molar density of the reactor mixture, V is the reactor volume, R_(j)is the reaction rate for species j, which has units of kmol/m³ s.

The total heat balance is solved for an adiabatic reactor and is givenby:

0=(Σ{dot over (m)} _(i) ΔH _(i) +q _(Rx) V+{dot over (W)}−{dot over(Q)})  (3)

where, {dot over (m)}_(i) is the mass flow rate of stream i (inlet oroulet), ΔH_(i) is the difference in enthalpy of stream i versus areference state, q_(Rx) is the heat released by reaction(s), V is thereactor volume, {dot over (W)} is the work input (i.e. agitator), {dotover (Q)} is the heat input/loss.

The catalyst concentration input to each reactor is adjusted to matchthe experimentally determined ethylene conversion and reactortemperature values in order solve the equations of the kinetic model(e.g. propagation rates, heat balance and mass balance).

The H₂ concentration input to each reactor may be likewise adjusted sothat the calculated molecular weight distribution of a polymer made overboth reactors (and hence the molecular weight of polymer made in eachreactor) matches that which is observed experimentally.

The degree of polymerization (DPN) for a polymerization reaction isgiven by the ratio of the rate of chain propagation reactions over therate of chain transfer/termination reactions:

$\begin{matrix}{{D\; P\; N} = \frac{{k_{p\; 11}{\phi_{1}\left\lbrack m_{1} \right\rbrack}} + {k_{p12}{\phi_{1}\left\lbrack m_{2} \right\rbrack}} + {k_{p21}{\phi_{2}\left\lbrack m_{2} \right\rbrack}}}{\begin{matrix}{{{k_{{tm}\; 11}\left\lbrack m_{1} \right\rbrack}\phi_{1}} + {{k_{{tm}\; 12}\left\lbrack m_{2} \right\rbrack}\phi_{1}} + {{k_{{tm}\; 21}\left\lbrack m_{2} \right\rbrack}\phi_{2}} +} \\{{k_{{ts}\; 1}\phi_{1}} + {k_{{ts}\; 2}\phi_{2}} + {k_{{tH}\; 1}\lbrack H\rbrack} + {k_{{tH}\; 2}\lbrack H\rbrack}}\end{matrix}}} & (4)\end{matrix}$

where k_(p12) is the propagation rate constant for adding monomer 2 to agrowing polymer chain ending with monomer 1, [m₁] is the molarconcentration of monomer 1 (ethylene) in the reactor, [m₂] is the molarconcentration of monomer 2 (1-octene) in the reactor, k_(tm12) thetermination rate constant for chain transfer to monomer 2 for a growingchain ending with monomer 1, k_(ts1) is rate constant for thespontaneous chain termination for a chain ending with monomer 1, k_(tH1)is the rate constant for the chain termination by hydrogen for a chainending with monomer 1. ϕ₁ and ϕ₂ and the fraction of catalyst sitesoccupied by a chain ending with monomer 1 or monomer 2 respectively.

The number average molecular weight (M_(n)) for a polymer follows fromthe degree of polymerization and the molecular weight of a monomer unit.From the number average molecular weight of polymer in each reactor, andassuming a Flory distribution for a single site catalyst, the molecularweight distribution is determined for the polymer formed in eachreactor:

w(n)=τ² ne ^(−τn)  (5)

where

${\tau = \frac{1}{DPN}},$

and w(n) is the weight Traction of polymer having a chain length n. TheFlory distribution can be transformed into the common log scaled GPCtrace by applying:

$\begin{matrix}{\frac{dW}{d\;{\log(M)}} = {{\ln\left( {10} \right)}\frac{n^{2}}{{DPN}^{2}}e^{({- \frac{n}{DPN}})}}} & (6)\end{matrix}$

where

$\frac{dW}{d\;{\log({MW})}}$

is the differential weight fraction of polymer with a chain length n(n=MW/28 where 28 is the molecular weight of the polymer segmentcorresponding to a C₂H₄ unit) and DPN is the degree of polymerization ascalculated by Equation (4). From the Flory model, the M_(w) and theM_(z) of the polymer made in each reactor are: M_(w)=2×M_(n) andM_(z)=1.5×M_(w).

The overall molecular weight distribution over both reactors is simplythe sum of the molecular weight distribution of polymer made in eachreactor, and where each Flory distribution is multiplied by the weightfraction of polymer made in each reactor:

$\begin{matrix}{\frac{d\overset{\_}{W}}{d\;{\log({MW})}} = {{W_{R1}\left( {{\ln\left( {10} \right)}\frac{n^{2}}{{DPN}_{R\; 1}^{2}}e^{({- \frac{n}{{DPN}_{R1}}})}} \right)} + {W_{R\; 2}\left( {\ln\; 10\;\frac{n^{2}}{{DPN}_{R\; 2}^{2}}e^{({- \frac{n}{{DPN}_{R2}}})}} \right)}}} & (7)\end{matrix}$

where dW/d log(MW) is the overall molecular weight distributionfunction, w_(R1) and w_(R2) are the weight fraction of polymer made ineach reactor, DPN_(i) and DPN₂ is the average chain length of thepolymer made in each reactor (i.e. DPN₁=M_(nR1)/28). The weight fractionof material made in each reactor is determined from knowing the massflow of monomer and comonomer into each reactor along with knowing theconversions for monomer and comonomer in each reactor.

The moments of the overall molecular weight distribution (or themolecular weight distribution of polymer made in each reactor) can becalculated using equations 8a, 8b and 8c (a Flory Model is assumedabove, but the below generic formula apply to other model distributionsas well):

$\begin{matrix}{\overset{\_}{M_{n}} = \frac{\sum_{i}w_{i}}{\sum_{i}\frac{w_{i}}{M_{i}}}} & \left( {8a} \right) \\{\overset{\_}{M_{w}} = \frac{\sum_{t}{w_{i}M_{i}}}{\sum_{i}w_{i}}} & \left( {8b} \right) \\{\overset{\_}{M_{z}} = \frac{\sum_{i}{w_{i}M_{i}^{2}}}{\sum_{i}{w_{i}M_{i}}}} & \left( {8c} \right)\end{matrix}$

The comonomer content in the polymer product (in each reactor) may alsobe calculated using the terminal kinetic model and long chainapproximations discussed above (see A. Hamielec, J. MacGregor, and A.Penlidis. Comprehensive Polymer Science and Supplements, volume 3,chapter Copolymerization, page 17, Elsevier, 1996).

For a given catalyst system, the comonomer (e.g. 1-octene) incorporationis a function of the monomer (e.g. ethylene) conversion, the comonomerto monomer ratio in the reactor (γ) and the reactivity ratio of monomer1 (e.g. ethylene) over monomer 2 (e.g. 1-octene): r₁=k_(p11)/k_(p12).

For a CSTR, the molar ratio of ethylene to comonomer in the polymer (Y)can be estimated knowing the reactivity ratio r₁ of the catalyst systemand knowing the ethylene conversion in the reactor (Q_(m1)). A quadraticequation can be derived using the May and Lewis equation forinstanstaneous comonomer incorporation (see “Copolymerization” by A.Hamielec, J. MacGregor, and A. Penlidis in Comprehensive Polymer Scienceand Supplements, volume 3, Chapter 2, page 17, Elsevier, 1996) andsolving the mass balance around the reaction. The molar ratio ofethylene to 1-octene in the polymer is the negative root of thefollowing quadratic equation:

$\begin{matrix}{{{{- Y^{2}}\frac{\gamma}{4}} + {\left\lbrack {r_{1} + {Q_{m1}\left( {1 - r_{1}} \right)} + \frac{\gamma}{4}} \right\rbrack Y} - Q_{m1}} = 0} & (9)\end{matrix}$

where Y is the molar ratio of ethylene to 1-octene in the polymer, γ isthe mass flow ratio of 1-octene to ethylene going the reactor, r₁ is thereactivity ratio of monomer 1 to monomer 2 for the catalyst system(r₁=k_(p11)/k_(p12)) and Q_(m1) is the ethylene monomer fractionalconversion.

The branching frequency can then be calculated knowing the molar ratioof monomer 1 to monomer 2 in the polymer:

$\begin{matrix}{{BF} = \frac{500}{Y + 1}} & (10)\end{matrix}$

where Y, is the molar ratio of monomer 1 (ethylene) over monomer 2(1-octene) in the polymer, and BF is the branching frequency (branchesper 1000 carbon atoms).

The overall branching frequency distribution (BFD) of the ethylenecomposition can be calculated by knowing the molecular weightdistribution and weight fraction of polymer made in each reactor, andthe average branching frequency (BF) of the ethylene copolymer made ineach reactor. The fraction of polymer made in each reactor can becalculated from the experimental mass flows and conversion of monomerand comonomer in each reactor. The branching frequency distributionfunction is obtained by calculating the average branch content for eachmolecular weight value of the overall molecular weight distributionfunction made from the two Flory distributions:

$\begin{matrix}{{BF_{MW}} = \frac{{w_{R1}{BF}_{R1}{F_{1}\left( {MW}_{R1} \right)}} + {w_{R2}{BF}_{R2}{F_{2}\left( {MW}_{R2} \right)}}}{{w_{R1}{F_{1}\left( {MW}_{R1} \right)}} + {w_{R2}{F_{2}\left( {MW}_{R2} \right)}}}} & (11)\end{matrix}$

where BF_(MW) is the branching at molecular weight (MW), w_(R1) andW_(R2) are the weight fraction of polymer made in Reactor 1 and Reactor2, BF_(R1) and BF_(R2) are the average branching frequency of polymermade in R1 and R2 (from Equations 9 and 10), F₁(MW_(R1)) and F₂(MW_(R2)) are Flory distribution function from Reactor 1 and Reactor 2.

The overall branching frequency of the polyethylene composition is givenby the weighted average of the branching frequency of the polymer madein each reactor:

BF_(avg) =w ₁BF₁ +w ₂BF₂  (12)

where, BF_(avg) is the average branching frequency for the total polymer(e.g. the polyethylene composition), w₁ and w₂ are the weight fractionof material made in each reactor, BF₁ and BF₂ are the branchingfrequency of material made in each reactor (e.g. the branching frequencyof the first and second ethylene copolymers).

For the polymer obtained in each reactor, the key resin parameters whichare obtained from the above described kinetic model are the molecularweights Mn, Mw and Mz, the molecular weight distributions M_(w)/M_(n)and M_(z)/M_(w) and the branching frequency (SCB/1000 Cs). With thisinformation in hand, a component (or composition) density model and acomponent (or composition) melt index, I₂, model was used according tothe following equations, which were empirically determined, to calculatethe density and melt index I₂ of each of the first and second ethylenecopolymers:

Density:

$\frac{1}{\rho} = {{{1.0}142} + {{0.0}033\left( {1{{.22} \cdot {BF}}} \right)^{0.8346}} + \frac{{0.0}303\mspace{14mu} k^{{0.9}804}}{1 + \frac{03712}{e^{1.22{BF}}}}}$

where, BF is the branching frequency, k=Log₁₀ (M_(n)/1000)

Melt Index, I₂ (MI):

${{Log}_{10}({MI})} = {{{7.8}998} - {{3.9}089\;{{Log}_{10}\left( \frac{M_{w}}{1000} \right)}} - {{0.2}799\frac{M_{n}}{M_{w}}}}$

Hence, the above models were used to estimate the branch frequency,weight fraction (or weight percent), melt index and the density of thepolyethylene composition components, which were formed in each ofreactor 1 and 2 (i.e. the first and second ethylene copolymers).

TABLE 1 Reactor Conditions Example No. 1 2 Reactor 1 Ethylene (kg/h)29.9 29.9 Octene (kg/h) 5.16 4.13 Hydrogen (g/h) 0.28 0.41 Solvent(kg/h) 244.5 245.6 Reactor Feed Inlet Temperature (° C.) 35 35 ReactorTemperature (° C.) 165.1 164.7 Titanium Catalyst (ppm) 0.0376 0.0287Reactor 1 Ethylene Conversion (%) 93 93 Reactor 2 Ethylene (kg/h) 44.944.9 Octene (kg/h) 0 0 Hydrogen (g/h) 5.5 5.5 Solvent (kg/h) 225.5 225.5Reactor Feed Inlet Temperature (° C.) 35 35 Reactor Temperature (° C.)200.1 200 Titanium Catalyst (ppm) 0.0743 0.0562 Reactor 2 EthyleneConversion (%) 86 86 Reactor Pressure (MPa) 16 16 Rate (kg/h) 72.1 71.8

TABLE 2 Resin Properties Example No. 1 1* (Inventive) 2 2* (Inventive)Nucleating Agent None HPN20E None HPN20E Density (g/cm³) 0.9449 0.94660.947 0.9489 Base Resin Density (g/cm³) 0.9449 0.947 density increaseafter 0.0017 0.0019 nucleation Melt Index I₂ (g/10 min), 11.3 11 baseresin Melt Index I₆ (g/10 min) 46.6 44.7 Melt Index I₁₀ (g/10 min) 8382.1 Melt Index I₂₁ (g/10 min) 300 289 Melt Flow Ratio (I₂₁/I₂) 26.526.1 Stress Exponent 1.29 1.27 Melt Flow Ratio (I₁₀/I₂) 7.57 7.51Rheological Properties Shear viscosity (η) at 10⁵ s⁻¹ 7.2 6.7 (240° C.,Pa-s) 100/η at 10⁵ s⁻¹ (240° C.), 13.9 14.9 Processability indicatorShear viscosity Ratio 37.7 42.1 η₁₀₀/η₁₀₀₀₀₀ (240° C.) Zero ShearViscosity - 860.65 854.43 190° C. (Pa-s) Crossover Frequency - — — 190°C. (rad/s) DRI 0.389 0.326 G′@G″ = 500 Pa 32 26.4 DSC Primary MeltingPeak (° C.) 126.05 129.02 126.73 130.18 Heat of Fusion (J/g) 196.4 211.6200.4 211.7 Crystallinity (%) 67.74 72.95 69.11 73.01 Branch Frequency -FTIR (uncorrected for chain end —CH₃) Branch Freq (SCB per 1000Cs) 3.83.1 Comonomer ID 1-octene 1-octene Comonomer Content (mole %) 0.8 0.8Comonomer Content (wt %) 3 3 Internal Unsat/100 C. 0.016 0.016 SideChain Unsat/100 C. 0.002 0.002 Terminal Unsat/100 C. 0.019 0.019 CTREFSLOW High Elution Peak (° C.) 93 93.3 CDBI₅₀ 83.6 84.5 Co/Ho 0.40 0.30HD Fraction - Approx. wt % 72.4 79.5 (95 to 105° C.) GPC M_(n) 2356319814 M_(w) 55988 54421 M_(z) 114231 115102 Polydispersity Index(M_(w)/M_(n)) 2.38 2.75 Extractables & Regulatory Testing HexaneExtractables (wt. %) - 0.24 0.14 Plaque Example No. 3 3* 4 4* 5 5*Nucleating Agent None HPN20E None HPN20E None HPN20E Density (g/cm³)0.9539 0.9564 0.954 0.9569 0.9546 0.9574 Base Resin Density (g/cm³)0.9539 0.954 0.9546 density increase after 0.0025 0.0029 0.0028nucleation Melt Index I₂ (g/10 min), 20.4 13.5 29.1 base resin MeltIndex I₆ (g/10 min) 75 53.1 103 Melt Index I₁₀ (g/10 min) 141 95 170Melt Index I₂₁ (g/10 min) 400 312 524 Melt Flow Ratio (I₂₁/I₂) 19.6 23.118 Stress Exponent 1.19 1.25 1.15 Melt Flow Ratio (I₁₀/I₂) 7.73 7.086.08 Rheological Properties Shear viscosity (η) at 10⁵ s⁻¹ 7.3 7.0 7.4(240° C., Pa-s) 100/η at 10⁵ s⁻¹ (240° C.), 13.7 14.3 13.5Processability Indicator Shear viscosity Ratio 24.1 34.8 16.9η₁₀₀/η₁₀₀₀₀₀ (240° C.) Zero Shear Viscosity - 401.46 685.04 276.45 190°C. (Pa-s) Crossover Frequency - — — — 190° C. (rad/s) DRI 0.15 0.2430.119 G′@G″ = 500 Pa 12.8 20.7 9.2 DSC Primary Melting Peak (° C.)129.84 131.38 130.42 132.03 130.27 132.35 Heat of Fusion (J/g) 218.1221.1 215.5 247.5 217.2 228.2 Crystallinity (%) 75.2 76.23 74.31 85.3474.89 78.7 Branch Frequency - FTIR (uncorrected for chain end —CH₃)Branch Freq (SCB per 1000Cs) 1.8 1.7 1.5 Comonomer ID 1-octene 1-octene1-octene Comonomer Content (mole %) 0.4 0.3 0.3 Comonomer Content (wt %)1.4 1.4 1.2 Internal Unsat/100 C. 0.017 0.018 0.017 Side Chain Unsat/100C. 0 0.001 0 Terminal Unsat/100 C. 0.021 0.022 0.019 CTREF SLOW HighElution Peak (° C.) 95.3 95.2 95.4 CDBI₅₀ 82.1 83.8 82.3 Co/Ho 0.2 0.10.1 HD Fraction - Approx. wt % 87.2 88.8 88.1 (95 to 105° C.) GPC M_(n)21653 24905 23930 M_(w) 49521 55953 46233 M_(z) 89061 109160 76726Polydispersity Index (M_(w)/M_(n)) 2.29 2.25 1.93 Extractables &Regulatory Testing Hexane Extractables (wt. %) - 0.19 0.15 0.14 Plaque

TABLE 3 Polyethylene Composition Component Properties Example No. 1 2 34 5 Density (g/cm³) 0.9449 0.947 0.9539 0.954 0.9546 I₂ (g/10 min.) 11.311 20.4 13.5 29.1 Stress Exponent 1.29 1.27 1.19 1.25 1.15 MFR (I₂₁/I₂)26.5 26.1 19.6 23.1 18 Mw/Mn 2.38 2.75 2.29 2.25 1.93 First EthyleneCopolymer Weight fraction 0.4164 0.4161 0.3066 0.3069 0.3063 Mw 129242122356 92001 117778 74433 I₂ (g/10 min.) 0.32 0.40 1.22 0.46 2.79SCB1/1000C 3.04 2.45 0.625 0.633 0.617 Density, d1 (g/cm³) 0.9282 0.93060.9441 0.9417 0.9463 Second Ethylene Copolymer Weight fraction 0.58360.5839 0.6934 0.6931 0.6937 Mw 28316 28885 37539 37851 37179 I₂ (g/10min.) 121.4 112.3 40.3 39.0 41.9 SCB2/1000C 1.16 0.93 0.2 0.2 0.2Density, d2 (g/cm³) 0.952 0.9531 0.957 0.957 0.9571 SCB1/SCB2 2.62 2.633.13 3.17 3.09 Estimated (d2 − d1), g/cm³ 0.0238 0.0225 0.0129 0.01530.0108

TABLE 4 Plaque Properties 1* 2* Example No. 1 (Inventive) 2 (Inventive)Tensile Properties (Plaques) Elong. at Yield (%) 9 10 11 9 Elong. atYield Dev. (%) 0.1 0.1 0 0.2 Yield Strength (MPa) 24.2 25.6 24.9 26.6Yield Strength Dev. (MPa) 0.3 0.1 0.1 0.1 Ultimate Elong. (%) 279 237441 407 Ultimate Elong. Dev. (%) 142 83 31.1 — Ultimate Strength (MPa)14.4 14.3 14.7 14.5 Ultimate Strength Dev. (MPa) 0.3 0.4 0.6 8.8 Sec Mod1% (MPa) 964 1092 1055 1163 Sec Mod 1% (MPa) Dev. 49 11 23 26 Sec Mod 2%(MPa) 763 842 803 893 Sec Mod 2% (MPa) Dev. 19 6 9 10 Youngs Modulus(MPa) 1499.9 966 — Youngs Modulus (MPa) Dev. 236.2 91 — FlexuralProperties (Plaques) Flex Secant Mod. 1% (MPa) 945 1077 978 1092 FlexSec Mod 1% (MPa) Dev. 20 26 29 16 Flex Secant Mod. 2% (MPa) 805 911 819927 Flex Sec Mod 2% (MPa) Dev. 18 21 27 10 Flex Tangent Mod. (MPa) 12031392 1263 1358 Flex Tangent Mod. Dev. (MPa) 59 70 27 73 FlexuralStrength (MPa) 30.6 33.6 30.5 33.9 Flexural Strength Dev. (MPa) 0.5 0.40.8 0.5 Impact Properties (Plaques) Izod Impact (ft-lb/in) 1.04 0.990.97 0.93 Environmental Stress Crack Resistance ESCR Cond. B at 100%CO-630 (hrs) 7 7 6 6 Miscellaneous VICAT Soft. Pt. (° C.) - Plaque 123.9125.2 — Heat Deflection Temp. (° C.) @66 PSI 67 — — Example No. 3 3* 44* 5 5* Tensile Properties (Plaques) Elong. at Yield (%) 10 9 10 9 10 9Elong. at Yield Dev. (%) 0.1 0.3 0.1 0.1 0.1 0.3 Yield Strength (MPa)28.8 29.9 28.5 30.9 29.6 30.4 Yield Strength Dev. (MPa) 0.3 0.6 0.2 0.20.2 0.2 Ultimate Elong. (%) 213 652 535 1377 118 775 Ultimate Elong.Dev. (%) 159 672 412 70 87 656 Ultimate Strength (MPa) 18.9 13.9 15.719.9 19.3 14.2 Ultimate Strength Dev. (MPa) 7.2 3 1 2.1 8.1 1.3 Sec Mod1% (MPa) 1226.8 1296 1219 1418 1266 1371 Sec Mod 1% (MPa) Dev. 56 122 3917 54 33 Sec Mod 2% (MPa) 959 1002 944 1071 990 1045 Sec Mod 2% (MPa)Dev. 26 59 16 6 20 6 Youngs Modulus (MPa) 1594.6 1633.1 313.3 YoungsModulus (MPa) Dev. Flexural Properties (Plaques) Flex Secant Mod. 1%(MPa) 1262 1369 1250 1455 1259 1258 Flex Sec Mod 1% (MPa) Dev. 30 30 1644 39 22 Flex Secant Mod. 2% (MPa) 1063 1143 1060 1214 1065 1051 FlexSec Mod 2% (MPa) Dev. 26 9 12 35 35 20 Flex Tangent Mod. (MPa) 1493 16641456 1747 1471 1531 Flex Tangent Mod. Dev. (MPa) 65 153 52 32 86 39Flexural Strength (MPa) 38 38.8 37.8 42.2 38.1 35.9 Flexural StrengthDev. (MPa) 0.6 0.3 0.3 0.3 0.9 0.6 Impact Properties (Plaques) IzodImpact (ft-lb/in) 0.80 0.75 0.88 0.81 0.75 0.71 Environmental StressCrack Resistance ESCR Cond. B at 100% CO-630 (hrs) 1 2 0 MiscellaneousVICAT Soft. Pt. (° C.) - Plaque 127.5 127 127.6 Heat Deflection Temp. (°C.) @66 PSI 78.3 79.3 79.9

As can been seen from the data in Table 4, plaques made from theinventive copolymer compositions of Examples 1 and 2 had ESCR valueswhich were superior (i.e. higher) than for plaques made from thecomparative copolymer compositions of Examples 3-5. Alternatively, FIG.5, shows that the nucleated inventive copolymer compositions provide foran improved balance of ESCR and OTR properties relative to the nucleatedcomparative copolymer compositions.

As can be seen from the data in Table 4, plaques made from nucleatedinventive copolymer compositions (Examples 1* and 2*) had notched Izodimpact resistances which were higher than for plaques made fromnucleated comparative copolymer compositions (Examples 3*-5*).Alternatively, FIG. 6, shows that the nucleated inventive copolymercompositions provide for an improved balance of impact strength (notchedIzod) and OTR properties relative to the nucleated comparative copolymercompositions.

Method of Making Compression Molded Film

A laboratory scale compression molding press Wabash G304 from Wabash MPIwas used to prepare compression molded film from the inventive andcomparative polyethylene compositions. A metal frame of requireddimensions and thickness was filled with a measured quantity of resin(e.g. pellets of a polyethylene composition) and sandwiched between twopolished metal plates. The measured polymer quantity used was sufficientto obtain the desired film thickness. Polyester sheets (Mylar) were usedon top of the metal backing plates to prevent the sticking of the resinto the metal plates. This assembly with the resin was loaded in thecompression press and preheated at 200° C. under a low pressure (e.g. 2tons or 4400 lbs per square foot) for five minutes. The platens wereclosed and a high pressure (e.g., 28 tons or 61670 lbs per square foot)was applied for another five minutes. After that, the press was cooledto about 45° C. at a rate of about 15° C. per minute. On completion ofthe cycle, the frame assembly was taken out, disassembled and the film(or plaque) was separated from the frame. Subsequent tests were doneafter at least 48 hours after the time at which the compression moldingwas carried out.

Determination of the Oxygen Transmission Rate (OTR) of a CompressionMolded Film Using a Masking Method

The oxygen transmission rate (OTR) of the compression-molded film wastested using an OX-TRAN® 2/20 instrument manufactured by MOCON Inc,Minneapolis, Minn., USA using a version of ASTM F1249-90. The instrumenthad two test cells (A and B) and each film sample was analyzed induplicate. The OTR result reported was the average of the results fromthese two test cells (A and B). The test was carried out at atemperature of 23° C. and at a relative humidity of 0%. Typically, thefilm sample area used for OTR testing was 100 cm². However, for barriertesting of films where there is a limited amount of sample, an aluminumfoil mask is used to reduce the testing area. When using the mask, thetesting area was reduced to 5 cm². The foil mask had adhesive on oneside to which the sample was attached. A second foil was then attachedto the first to ensure a leak free seal. The carrier gas used was 2%hydrogen gas in a balance of nitrogen gas and the test gas was ultrahigh purity oxygen. The OTR of the compression molded films were testedat the corresponding film thickness as obtained from the compressionmolding process. However, in order to compare different samples, theresulting OTR values have been normalized to a film thickness value of 1mil.

Determination of the Water Vapor Transmission Rate (WVTR) of aCompression Molded Film Using a Masking Method

The water vapor transmission rate (WVTR) of the compression-molded filmwas tested using a PERMATRAN® 3/34 instrument manufactured by MOCON Inc,Minneapolis, Minn., USA using a version of ASTM D3985. The instrumenthad two test cells (A and B) and each film sample was analyzed induplicate. The WVTR result reported was the average of the results fromthese two test cells (A and B). The test is carried out at a temperatureof 37.8° C. and at a relative humidity of 100%. Typically, the filmsample area used for WVTR testing was 50 cm². However, for barriertesting of films where there was a limited amount of sample, an aluminumfoil mask was used to reduce the testing area. When using the mask, thetesting area was reduced to 5 cm². The foil mask has adhesive on oneside to which the sample was attached. A second foil was then attachedto the first to ensure a leak free seal. The carrier gas used was ultrahigh purity nitrogen gas and the test gas was water vapor at 100%relative humidity. The WVTR of the compression molded films was testedat the corresponding film thickness as obtained from the compressionmolding process. However, in order to compare different samples, theresulting WVTR values have been normalized to a film thickness value of1 mil.

The barrier properties (OTR and WVTR) of pressed films made fromcomparative and inventive polyethylene compositions are provided inTable 5.

TABLE 5 OTR and WVTR Properties of Compression Molded Films 1* 2*Example No. 1 (Inventive) 2 (Inventive) WVTR - thickness (mil) 1.75 2.32.65 2.35 WVTR g/100 IN²/Day (relative 0.1765 0.1285 0.1761 0.0940humidity = 100%, 37.8° C., atm) WVTR in g/100 IN²/Day - 0.3089 0.29560.4667 0.2209 normalized thickness (1 mil) Improvement in WVTR property4.3% 52.7% after nucleation OTR - thickness (mil) 1.75 2.3 2.65 2.35 OTRin cm³/100 in²/day (relative 91.08 50.82 88.55 40.92 humidity = 0%, 23°C., atm) OTR in cm³/100 IN²/Day - 159.3900 116.89 234.6575 96.16normalized thickness (1 mil) Improvement in OTR property 26.7% 59.0%after nucleation Example No. 3 3* 4 4* 5 5* WVTR - thickness (mil) 2.92.4 1.7 2.1 2.85 1.85 WVTR g/100 IN²/Day (relative 0.1279 0.0949 0.17060.0965 0.0822 0.1109 humidity = 100%, 37.8° C., atm) WVTR in g/100IN²/Day - 0.3709 0.2278 0.2900 0.2027 0.2343 0.2052 normalized thickness(1 mil) Improvement in WVTR property 38.59% 30.13% 12.42% afternucleation OTR - thickness (mil) 2.9 2.4 1.7 2.1 2.85 1.85 OTR incm³/100 in²/day (relative 54.23 31.22 99.21 40.16 47.61 49.79 humidity =0%, 23° C., atm) OTR in cm³/100 IN²/Day - 157.2670 74.93 168.6570 84.34135.6885 92.11 normalized thickness (1 mil) Improvement in OTR property52.4% 50.0% 32.1% after nucleation

As can been seen from the data in Table 5, as well as FIGS. 2 and 3, afilm made from a nucleated inventive copolymer composition (Example 2*)had OTR and WVTR values which were comparable to films made fromcomparative copolymer compositions when similarly nucleated (Examples3*, 4* and 5*), even though the nucleated inventive composition (Example2*) had a much lower density.

Method of Making a Closure by Injection Molding

Nucleated versions of the Inventive polyethylene copolymer compositionsas well as the comparative resins were made into closures using aninjection molding process. A Sumitomo injection molding machine and2.15-gram PCO (plastic closure only) 1881 carbonated soft drink (CSD)closure mold was used to prepare the closures herein. A Sumitomoinjection molding machine (model SE75EV 0250M) having a 28 mm screwdiameter was used. The 4-cavity CSD closure mold was manufactured byZ-moulds (Austria). The 2.15-gram PCO 1881 CSD closure design wasdeveloped by Universal Closures Ltd. (United Kingdom). During theclosure manufacturing, four closure parameters, the diameter of the topof the cap, the bore seal diameter, the tamper band diameter and theoverall cap height, were measured and ensured to be withinquality-control specifications.

An International Society of Beverage Technologists (ISBT) voluntarystandard test method was used to determine the closure dimensions. Thetest used involves the selection of a mold cavity and the measurementson at least 5 closures made from that particular cavity. At least 14dimensional measurements were obtained from closures that were aged forat least 1 week from the date of production. The closure dimensionmeasurements were performed using a Vision Engineering, Swift Duo dualoptical and video measuring system. All measurements were taken using10× magnification and utilizing METLOGIX® M video measuring systemsoftware (see METLOGIX M³: Digital Comparator Field of View Software,User's Guide).

The closures were formed by injection molding, and the injection-moldingprocessing conditions are given in Table 6.

TABLE 6 Injection Molding Processing Conditions Example No. 1* (Inv.) 2*(Inv.) 3* 4* 5* Closure No. 1 2 3 4 5 Additives (Color & Formulation)Natural Natural Natural Natural Natural Part Weight (g) 8.60 8.60 8.608.6 8.6 Injection Speed (mm/s) 45 45 45 45 45 Cycle time (s) 4.49 4.074.41 4.36 4.35 Filling time (s) 0.673 0.662 0.684 0.651 0.640 Dosingtime (s) 1.71 1.715 1.68 1.706 1.64 Minimum Cushion (mm) 9.75 9.75 9.799.756 9.76 Filling peak pressure (psi) 10774 10688 10043 10132 8433 Fullpeak pressure (psi) 10789 10706 10101 10151 8447 Hold end position (mm)13.56 12.76 15.00 12.63 12.77 Clamp force (ton) 20 20 19 20 20 Fillstart position (mm) 40.01 39.49 40.51 39.00 38.51 Dosing back pressure(psi) 844 844 841 842 840 Pack pressure (psi) 10777 10692 10067 101408434 Filling time 1 (s) 0.672 0.664 0.688 0.648 0.640 Temperature zone 1(° C.) 180 180 180 180 180 Temperature zone 2 (° C.) 185 185 185 185 185Temperature zone 3 (° C.) 190 190 190 190 190 Temperature zone 4 (° C.)200 200 200 200 200 Temperature zone 5 (° C.) 200 200 200 200 200 Moldtemperature stationary (° C.) 10 10 10 10 10

Oxygen Transmission Rate (OTR) of an Injection Molded Closure

To measure the oxygen transmission rate through a closure, ASTM D3985(Standard Test Method for Oxygen Gas Transmission Rate Through PlasticFilm and Sheeting Using a Coulometric Sensor) was adapted as follows.

First the closure's tamper evident band was removed. Next, the bottomedge of the closure was lightly roughed with sandpaper (for betteradhesion to the epoxy) and then the closure was epoxied (using DEVCON® 2part epoxy) to a testing plate so as to cover an outlet tube (for sweepgas) and inlet tube for N₂ introduction. The epoxy was allowed to dryovernight. One of the two gas tubes protruding into the closure interiorcarried inlet nitrogen gas flowing into the closure interior (nitrogenfeed line), while the other one carried sweep gas (e.g. nitrogen pluspermeates from the atmosphere surrounding the closure) out of theclosure interior and into a detector. If any oxygen present in theatmosphere was permeating the closure walls it was detected as acomponent within the N₂ exiting the closure interior as sweep gas. Theplate/closure/tubing apparatus was connected to an OX-TRAN low rangeinstrument (PERMATRAN-C® Model 2/21 MD) with the testing plate placed inan environmental chamber controlled at a temperature of 23° C. Abaseline measurement for the detection of atmospheric oxygen was alsotaken by using an impermeable aluminum foil (in parallel with theclosure) for a side by side comparison of permeability. The oxygenpermeability of the closure is reported as the average oxygentransmission rate in units of cm³/closure/day.

The oxygen barrier properties of injected molded closures made fromcomparative and inventive polyethylene compositions, all of which havebeen nucleated are provided in Table 7.

TABLE 7 Example Closure OTR Average No. No. (cm³/closure/day) Test Gas1* 1 0.0027 ambient air (20.9% oxygen) (Inventive) 2* 2 0.0026 ambientair (20.9% oxygen) (Inventive) 3* 3 0.0026 ambient air (20.9% oxygen) 4*4 0.0024 ambient air (20.9% oxygen) 5* 5 0.0025 ambient air (20.9%oxygen)

As can been seen from the data in Table 7, as well as FIG. 4, theclosures made from the nucleated inventive copolymer compositions(Examples 1* and 2*) had OTR values which were comparable to closuresmade from the comparative copolymer compositions (Examples 3*,4* and 5*)which are similarly nucleated, even though the inventive compositionsare of much lower density. Hence, the nucleated compositions of thepresent invention have a particularly good balance of impact strength(Izod) values, ESCR values and oxygen transmission rates (in a closure),making them particularly well suited for compression molded or injectionmolded closure applications in which barrier properties may bedesirable.

Furthermore, the use of a lower density polyethylene copolymercomposition as described by the present disclosure, may have advantagesin the manufacture of articles which may benefit from good barrierproperties, such as for example a cap or closure for a bottle, containeror the like, or a fitment for a pouch or the like.

INDUSTRIAL APPLICABILITY

A dual reactor solution polymerization process provides polyethylenecompositions which have a balance of properties such as barrierproperties, toughness properties, and environmental resistanceproperties. The polyethylene compositions may be useful in end useapplications such as closures for bottles or films having barrierproperties.

1. A polyethylene copolymer composition comprising: (1) 10 to 70 wt % ofa first ethylene copolymer having a melt index I₂, of from 0.1 to 10g/10 min; a molecular weight distribution M_(w)/M_(n), of less than 3.0;and a density of from 0.900 to 0.946 g/cm³; and (2) 90 to 30 wt % of asecond ethylene copolymer having a melt index I₂, of from 25 to 1,500g/10 min; a molecular weight distribution M_(w)/M_(n), of less than 3.0;and a density higher than the density of the first ethylene copolymer,but less than 0.970 g/cm³; wherein the density of the second ethylenecopolymer is less than 0.037 g/cm³ higher than the density of the firstethylene copolymer; the ratio (SCB1/SCB2) of the number of short chainbranches per thousand carbon atoms in the first ethylene copolymer(SCB1) to the number of short chain branches per thousand carbon atomsin the second ethylene copolymer (SCB2) is greater than 1.0; and whereinthe polyethylene copolymer composition has a molecular weightdistribution M_(w)/M_(n), of from 1.8 to 7.0; a density of less than0.949 g/cm³; a high load melt index I₂₁, of at least 150 g/10 min; aZ-average molecular weight M_(z), of less than 200,000; a melt flowratio I₂₁/I₂, of from 20 to 50; a stress exponent of less than 1.40; andan ESCR Condition B (100% IGEPAL) of at least 3.5 hours; and wherein thepolyethylene copolymer composition further comprises a nucleating agent.2. The polyethylene copolymer composition of claim 1 wherein thepolyethylene copolymer composition has an ESCR Condition B (100% IGEPAL)of from 3.5 to 15 hours.
 3. The polyethylene copolymer composition ofclaim 1 wherein the polyethylene copolymer composition has a melt indexI₂, of from greater than 5.0 to less than 20.0 g/10 min.
 4. Thepolyethylene copolymer composition of claim 1 wherein the density of thesecond ethylene copolymer is less than 0.030 g/cm³ higher than thedensity of the first ethylene copolymer.
 5. The polyethylene copolymercomposition of claim 1 wherein the first ethylene copolymer has a meltindex I₂, of from 0.1 to 5.0 g/10 min.
 6. The polyethylene copolymercomposition of claim 1 wherein the second ethylene copolymer has a meltindex I₂, of from 25 to 500 g/10 min.
 7. The polyethylene copolymercomposition of claim 1 wherein the polyethylene copolymer compositionhas a high load melt index I₂₁, of at least
 200. 8. The polyethylenecopolymer composition of claim 1 wherein the polyethylene copolymercomposition has a high load melt index I₂₁, of from 200 to 500 g/10 min.9. The polyethylene copolymer composition of claim 1 wherein thepolyethylene copolymer composition has a bimodal molecular weightdistribution as determined by gel permeation chromatography.
 10. Thepolyethylene copolymer composition of claim 1 wherein the ratio(SCB1/SCB2) of the number of short chain branches per thousand carbonatoms in the first ethylene copolymer (SCB1) to the number of shortchain branches per thousand carbon atoms in the second ethylenecopolymer (SCB2) is at least 2.0.
 11. The polyethylene copolymercomposition of claim 1 wherein the polyethylene copolymer compositionhas a molecular weight distribution M_(w)/M_(n), of from 2.0 to 4.0. 12.The polyethylene copolymer composition of claim 1 wherein the firstethylene copolymer has a density of from 0.920 to 0.940 g/cm³.
 13. Thepolyethylene copolymer composition of claim 1 wherein the secondethylene copolymer has a density of less than 0.965 g/cm³.
 14. Thepolyethylene copolymer composition of claim 1 wherein the secondethylene copolymer has a density of from 0.946 to 0.963 g/cm³.
 15. Thepolyethylene copolymer composition of claim 1 wherein the polyethylenecopolymer composition has a density of from 0.939 to less than 0.949g/cm³.
 16. The polyethylene copolymer composition of claim 1 wherein thepolyethylene copolymer composition has no long chain branching.
 17. Thepolyethylene copolymer composition of claim 1 wherein the polyethylenecopolymer composition has a composition distribution breadth indexCDBI(50) of greater than 65 wt %.
 18. The polyethylene copolymercomposition of claim 1 wherein the polyethylene copolymer compositioncomprises: from 20 to 55 wt % of the first ethylene copolymer; and from80 to 45 wt % of the second ethylene copolymer.
 19. The polyethylenecopolymer composition of claim 1 wherein the first and second ethylenecopolymers are copolymers of ethylene and 1-octene.
 20. The polyethylenecopolymer composition of claim 1 wherein the nucleating agent is presentin from 20 to 4000 parts per million based on the combined weight of thefirst ethylene copolymer and the second ethylene copolymer.
 21. Thepolyethylene copolymer composition of claim 1 wherein the nucleatingagent is a salt of a dicarboxylic acid compound.
 22. The polyethylenecopolymer composition of claim 1, which when made into a PCO 1881 CSDclosure, has an OTR of less than 0.0030 cm³/closure/day.
 23. A filmcomprising the polyethylene copolymer composition of claim 1 and ahaving a normalized OTR of ≤120 cm³/100 in²/day.
 24. A film comprisingthe polyethylene copolymer of claim 1 and having a normalized WVTR of≤0.320 g/100 in²/day.
 25. A closure for bottles, the closure comprisinga polyethylene copolymer comprising: (1) 10 to 70 wt % of a firstethylene copolymer having a melt index I₂, of from 0.1 to 10 g/10 min; amolecular weight distribution M_(w)/M_(n), of less than 3.0; and adensity of from 0.900 to 0.946 g/cm³; and (2) 90 to 30 wt % of a secondethylene copolymer having a melt index I₂, of from 25 to 1,500 g/10 min;a molecular weight distribution M_(w)/M_(n), of less than 3.0; and adensity higher than the density of the first ethylene copolymer, butless than 0.970 g/cm³; wherein the density of the second ethylenecopolymer is less than 0.037 g/cm³ higher than the density of the firstethylene copolymer; the ratio (SCB1/SCB2) of the number of short chainbranches per thousand carbon atoms in the first ethylene copolymer(SCB1) to the number of short chain branches per thousand carbon atomsin the second ethylene copolymer (SCB2) is greater than 1.0; and whereinthe polyethylene copolymer composition has a molecular weightdistribution M_(w)/M_(n), of from 1.8 to 7.0; a density of less than0.949 g/cm³; a high load melt index I₂₁, of at least 150 g/10 min; aZ-average molecular weight M_(z), of less than 200,000; a melt flowratio I₂₁/I₂, of from 20 to 50; a stress exponent of less than 1.40; andan ESCR Condition B (100% IGEPAL) of at least 3.5 hours; and wherein thepolyethylene copolymer composition further comprises a nucleating agent.26. A film, the film comprising a polyethylene copolymer compositioncomprising: (1) 10 to 70 wt % of a first ethylene copolymer having amelt index I₂, of from 0.1 to 10 g/10 min; a molecular weightdistribution M_(w)/M_(n), of less than 3.0; and a density of from 0.900to 0.946 g/cm³; and (2) 90 to 30 wt % of a second ethylene copolymerhaving a melt index I₂, of from 25 to 1,500 g/10 min; a molecular weightdistribution M_(w)/M_(n), of less than 3.0; and a density higher thanthe density of the first ethylene copolymer, but less than 0.970 g/cm³;wherein the density of the second ethylene copolymer is less than 0.037g/cm³ higher than the density of the first ethylene copolymer; the ratio(SCB1/SCB2) of the number of short chain branches per thousand carbonatoms in the first ethylene copolymer (SCB1) to the number of shortchain branches per thousand carbon atoms in the second ethylenecopolymer (SCB2) is greater than 1.0; and wherein the polyethylenecopolymer composition has a molecular weight distribution M_(w)/M_(n),of from 1.8 to 7.0; a density of less than 0.949 g/cm³; a high load meltindex I₂₁, of at least 150 g/10 min; a Z-average molecular weight M_(z),of less than 200,000; a melt flow ratio I₂₁/I₂, of from 20 to 50; astress exponent of less than 1.40; and an ESCR Condition B (100% IGEPAL)of at least 3.5 hours; and wherein the polyethylene copolymercomposition further comprises a nucleating agent.